` Dr.G.Rajesh

G Rajesh

Professor

Department of Aerospace Engineering

IIT Madras

Email : rajesh@ae.iitm.ac.in

Ph No : +91 44 2257 4032

Research Interests : Experimental Aerodynamics - High Speed Flows & Shockwave Dynamics

Current Research

Estimation of Mach Stem Heights in Asymmetric Shock Reflections on Wedges: The Mach stem heights in shockwave reflections in asymmetric flows have been predicted analytically. The MR configuration is predicted for all types of Mach reflections oustide and inside the dual domain. The results are validated with available experimental and numerical data. The Mach stem height in Inverse Mach Reflection where one of the slips lines is diverging has also been predicted accurately.
Flow Characteristics in Underexpanded Confined Jets: Studies underexpanded confined jets are being carried out. The evolutions of primary and secondary jets have been closely studied. The initail asymmetry exhibited by the primary jet is due to the asymmetric growth of vortex bubbles on either sides of the primary jet. The vacuum generation due to the induction of secondary flow is also decided by another set of vortex bubbles in the secondary flow. An interesting shock transfromation is observed after the primary jet is fully expanded to the outer duct walls.
Asymetric Reflection of Shockwaves on Short Wedges: Analytical and experimental studies are being carried out to predict transfromation criteria form regular reflection(RR) to Mach reflection(MR) on shorter wedges. It is found that the wedge trailing edge expansion fan is interacting with the shock reflection point and controls the RR-MR and MR-RR transfromations.
Unsteady Aerodynamics in the Transitional Ballistic Regimes: Experimental and computational studies on interior and launch dynamics of supersonic projectile are being carried out. We designed and developed a ballistic range to accelerate the projectiles to Mach numbers 1- 4. Studies are carried out on the unsteady aerodynamics of supersonically flying projectiles and their interaction with the flow field. Projectile drag history in the transitional ballistic regimes is being estimated with the help of time resolved schlieren images and computational simulations for various parameters. Sabot separation processes of penetrator projectiles and its influence on the unsteady aerodynamics is also studied. A short separation sabot is also being designed
Mach Reflection in Open Jets: The Mach stem heights in overexpanded and underexpanded jets having Mach reflections have been predicted analytically. RR-MR transformations are also predcited. The predicted Mach stem height vanishes exactly at the von-Nuemann condition. Numerical and experimental studies are being carried out to further investigate the transition criteria and hysteresis in overexpanded and underexpanded nozzles under steady and unsteady conditions.
Nozzle Flow Separation: Numerical and experimental studies are being carried out to analyse varaious separtion phenomena such as, Free Shock Separation (FSS) and Restricted Shock Separation(RSS) in thrust optimized parabolic (TOP) nozzles. It has been observed that intersting shock interactions inside the nozzle govern the separation phenomenon leading to FSS and RSS. A hysteresis is also found occuring in the FSS-RSS transformation, which is analogous to the hysteresis in the classical shock transformations
Altitude Adaptation Nozzles: An optimum profile for the second bell of an axi-symmetric dual bell nozzle which allows a sudden and controlled transition at a particular back pressure, so as to avoid a stable separation inside the second bell, using Method of Characteristics. The contour of the second bell is derived imposing various pressure gradient constraints. In another work, the performance evaluation of an annular aero-spike nozzle is being carried out. Cold and hot flow experiments have been carried out to predict thrust profile, pressure and temperature distributions along the nozzle and the base pressure.
Hypersonic Boundary layer Transition: A Mach-5 Ludweig tube (quiet flow tunnel) is being designed to study the boundary layer transition on axi-symmetric bodies
Blastwave mitigation: Blastwave mitigation studies using FRP materials are planned.
Blast Induced Trauma (BIT): Estimation of the human brain dislocation due to blastwaves are planned to be studied. The human skull model will be subjected to high blast loads from an open ended shock tube. Time resolved schlieren images will be used to visualize the flow fields and estimate the brain dislocations
Dynamics of Underwater Expansion Waves: Computations of underwater expansion waves and its reflection from an interface are planned.

Funded Projects

Theoretical Estimates of Blast Effects on Various Anti-Tank Threats: This is an ongoing one year consultancy project to carry out the analysis of an Active Protection System (APS) used to counter attack an anti-tank threat, funded by HEMRL.
A Study on Traumatic Brain Injury due to Weak Blast Loading on Helmet-head Assembly: This is an ongoing one year exploratory project is to carry out the study on Blast Induced Trauma caused by the weak blast loadigng on the head and helmet assmebly. This is funded by ICSR, IITM. The aim is to capture the blast aerodynamics and the structural response of the head-helmet model computationally and experimentally.
CFD simulations of the flow through Muzzle brakes and Bore Evacuator Projectiles: This ongoing one year consultancy project is to do the CFD simulations of the flow through improved muzzle brakes and bore evacuator barrels. The value of the project is Rs. 56,49,840/- and is funded by the Ordnance Factory-Ordnance Development Center Kanpur.
Simulation Study on an Implosion Driven Launcher: This is an ongoing consultancy project from ARDE, Pune, for simulating the projectile motion in an implosion driven launcher. This 1 year project is expected to deliver the design parameters for the implosion driven launcher to be built in ARDE. The project value is 9.995 Lakhs.
Variable Camber Morphing Wing: This is an ongoing sponsored research project in which I am a co-PI, from DRDO, for the design and the development of a variable camber morphing wing as part of the Center of Propulsion Technology Research Activities, IITM. The project value is 1286.1 Lakhs.
Experimental Study on Starting Transients in a Vacuum Ejector-Diffuser System: This two year project for Rs.27,61,020/- is funded by the AR&DB aerodynamics panel. This work is to experimentally investigate the short transients and its behavior during the start-up for of an ejector-diffuser system used as a vacuum pump, for various flow and configurations parameters, predict the presence of the recirculation zone and its behavior during the start-up of the vacuum ejector system, predict the nature of oscillations in the secondary and mixing chamber and its damping and estimate the influence of various flow and configuration parameters in the damping of the oscillations.
Flow characterization studies and performance analysis of an annular aerospike nozzle: This is a closed, ISRO funded, 3 year project for developing an annular aerospike nozzle for Rs. 28,32,088/- In the present project, the flow characterization studies and performance evaluation of an annular aero-spike nozzle equivalent to the an existing engine of ISRO are being carried out. The performance of the engine is being obtained through a as series of cold and hot flow studies at ground level and high altitude conditions with varying back pressure conditions. The performance of the engine are evaluated through the thrust measurements under various nozzle configurations and flow conditions by capturing the pressure data and flow fields using flow visualization methods. The data captured will be used for actual engine development.
Flow Characteristics in Transitional Ballsitic regimes of Supersonic Projectiles: This is a closed, 3 year project funded by IC&SR, IITM for Rs. 38,36,000/- . The objective was to study the unsteady aerodynamics of supersonic projectile in transitional ballistic ragimes. A two stage gas gun is built to accelarte the projectile to supersonic speeds at required Mach numbers. Time resolved schlieren images have been obtained to visualize the transient flow fields and projectile flow-field interactions.
Computational study of the launch dynamics of supersonic projectiles: This is a closed, 1 year project. It was funded by Keimyung University for $6500. The project obejective was to computationally simulate the launch dyanmics of supersonic projectiles. The influence of viscosity and projectile shapes on the unsteady aerodynamics of the moving projectile in the vicinity of the launch tube was analized. Unsteady drag coefficent of the projectile was estimated for various conditions.

Journal Articles

29. G. Sivaprasad, Rajesh Gopalapillai, T. Jayachandran, and Arun Kumar Rajagopal, 2023, "Strong Shock Solutions in Symmetric Wedge Flows: Unphysical or Unstable?," Physics of Fluids, 35, 066104. DOI

28. Vagish D. Mishra, Ashish Mishra, Luv Verma, Rajesh G., Balkrishna C. Rao, H. Murthy, 2023, “Functional Gradation of Aluminum Alloy by Impact of Ballistics as Severe Plastic Deformation Process,” International Journal of Impact Engineering 174, 104488. DOI

27. Arun Kumar. R, G. Rajesh, and Jagadeesh G., 2022, “The Reflection and Refraction of a Curved Shock Front Sliding over an Air-Water Interface,” Shockwaves 32 (6), 497-515, DOI

26. DiviaHarshaVardini R C, Arul Prakash K., and G. Rajesh, 2022, “An All-speed Formulation Using a Modified γ-model for the Prediction of Boundary Layer Transition and Heat Transfer,” International Journal of Heat and Mass Transfer, Vol. 195, 123121. DOI

25. Vinoth Paramanantham, Sushmitha Janakiram, Rajesh Gopalapillai, 2022, "Prediction of Mach Stem Height in Compressible Open Jets, Part I. Overexpanded Jets," J. Fluid Mechanics, Vol. 942, A48. Open Access Article

24. Vagish D. Mishra, Ashish Mishra, Avinash Singh, Luv Verma and G. Rajesh, 2021, "Ballistic Impact Performance of UHMWP Fabric Impregnated with Shear Thickening Fluid Nanocomposite," Composite Structures, Vol.281, 114991. DOI

23. Rohtash Goyal, A. Sameen, T. Jayachandran and G. Rajesh, 2021, "Dynamic Effects in Transition from Regular to Mach Reflection in Steady Supersonic Flows," Physical Review E, 104, 055101. DOI

22. I. V. Thara Reshma, Paramanantham Vinoth, G. Rajesh, and G. Ben-Dor, 2021, "Propagation of a Planar Shock Wave along a Convex-Concave Ramp," J. Fluid Mechanics, Vol. 924, A37. Open Access Article

21. Sreelal M. R. and G. Rajesh, 2020, "Trajectory Predictions of New Lift Separation Sabots," Defence Technology, 17(4), 1361-1373. DOI

20. C. M. Athira, G. Rajesh, Sreelal Mohanan, and Aadhy Parthasarathy, 2020, "Flow Interactions on Supersonic Projectiles in Transitional Ballistic Regimes," J. Fluid Mechanics, 894, A27. DOI

19. K. M. Muhammed Rafi, M. Deepu and G. Rajesh, 2019, "Effect of Heat Transfer and Geometry on Micro-Thruster Performance," International Journal of Thermal Sciences, Vol. 146, 106063. DOI

18. R. Arun Kumar and G. Rajesh, 2019, "Effect of Geometric Configurations on the Starting Transients in Vacuum Ejector," AIAA Journal, 57 (7), 2905-2922. DOI

17. Shobhan Roy and Rajesh Gopalapillai, 2019, "An Analytical Model for Asymmetric Mach Reflection Configuration in Steady Flows," J. Fluid Mechanics, 863, 242-268. DOI

16. R. Arun Kumar and G. Rajesh, 2018, "Physics of Vacuum Generation in Zero-Secondary Flow Ejectors," Physics of Fluids, 30, 066102. (Selected as Editor's Pick.) DOI

15. R. Arun Kumar and G. Rajesh, 2017, "Shock Transformation and Hysteresis in Underexpanded Confined Jets," J. Fluid Mechanics, 823, 538-561. DOI

14. R. Arun Kumar and G. Rajesh, 2016, "Flow Transients in Un-started and Started Modes of Vacuum Ejector Operation," Physics of Fluids, 28, 056105. DOI

13. Ankit Mittal, G. Rajesh, V. Lijo, and H. D. Kim, 2014, "Starting Transients in a Vacuum Ejector-Diffuser System,” J. Propulsion and Power, 30(6), 1213-1223.DOI

12. C. K. Muthukumaran, G. Rajesh, and H. D. Kim, 2013, “Launch Dynamics of Supersonic Projectiles,” J. of Spacecraft and Rockets, 50 (6), 1150-1161.DOI

11. T. Nakabaru, T. Hashimoto, S. Matsuo, T. Setoguchi, and and G Rajesh, 2013, "Generating and focusing of underwater expansion wave using a silicon resin reflector," J. of Thermal Science, 22 (3), 209-215.

10. JianGuo Sun, Heuy Dong Kim, Yingzi Jin, and G. Rajesh, 2013, “Analytical Study on the Gas-Solid Suspension Flows Through Sonic and Supersonic Nozzles,” J. of Korean Society of Propulsion Engineers, 1, 9-17.

9. G. Rajesh, Gyanesh Kumar, H D Kim, and Mathew George, 2012, “Computational and Experimental Simulations of the Flow Characteristics of an Aerospike Nozzle,” Korean Journal of Visualization, 10(1), 47-54.

8. V. Lijo, H. D. Kim, G Rajesh, and T. Setoguchi, 2010, “Numerical Simulation of Transient Flows in a Vacuum Ejector-Diffuser System,” J. Aerospace Engineering, IMechE, 224(7), 777-786.

7. G. Rajesh, H. D. Kim, and T. Setoguchi, 2008, “The Projectile Aerodynamics Overtaking a Shock Wave,” J. Spacecraft and Rockets, 45(6) pp.1251-1261.

6. G. Rajesh, R. Mishra, H. G. Kang, and H. D. Kim, 2007, “Computational Study of the Compressible Flow Driven by a Piston in a Ballistic Range,” J. Thermal Sciences, Springer, 16(4), 360-369.

5. G. Rajesh, H. D. Kim, T. Setoguchi, and S. Raghunathan, 2007, “Performance Analysis and Enhancement of the Ballistic Range,” J. Aerospace Engineering, IMechE, 221(5), 649-659.

4. G. Rajesh, H. D. Kim, S. Matsuo, and T. Setoguchi, 2007, “A Study of the Unsteady Projectile Aerodynamics Using a Moving Coordinate Method,” J. Aerospace Engineering, IMechE, 221(5), 691-706.

3. Rajesh Gopalapillai, Heuy-Dong Kim, Toshiaki Setoguchi and Shigeru Matsuo, 2007, “On the Near-Field Aerodynamics of a Projectile Launched from a Ballistic Range,” J. Mechanical Science and Technology, 21(7), 1129-1138.

2. G. Rajesh, J. M. Lee, S.C. Back, and H. D. Kim, 2006, “Theoretical Study for the Design of a New Ballistic Range,” J. Mechanical Science and Technology, 20(7), 1019-1029.

1. H. D. Kim, G Rajesh, T. Setoguchi, and S. Matsuo, 2006, “Optimization Study of a Coanda Ejector,” J. Thermal Sciences, 15(4), 331-336.

National and International Conferences

60. Thara Reshma I V, Vishnu Prasad. S, P. Vinoth, and G Rajesh, 2023, “Unsteday Shock Reflections Over Curved Surfaces,” 7th National Symposium on Shockwaves, February, PRL, Ahmedabad.

59. DiviaHarshaVardini R C, G Rajesh, and Arul Prakash K, 2023, “Numerical Analysis on Boundary Layer Suction in Hypersonic flows using a Modified Transition Model,” 7th National Symposium on Shockwaves, February, PRL, Ahmedabad.

58. Sreelal M R and G Rajesh, 2022, “Kinetic Energy Projectile Launch Using Lift Separation Sabots,” Ballistics 2022, Vol-1, Emerging Technologies, Explosion Mechanics, Interior Ballistics, Launch Dynamics, and Vulnerability and Survivability, Proceeding of 32nd International Symposium, May 9-13, Reno, Nevada.

57. Athira C M and G Rajesh, 2022, “Analytical Estimation of the Projectile Trajectory and Drag Characteristics in the Interior and Transitional Ballistic Regimes,” Ballistics 2022, Vol-1, Emerging Technologies, Explosion Mechanics, Interior Ballistics, Launch Dynamics, and Vulnerability and Survivability, Proceeding of 32nd International Symposium, May 9-13, Reno, Nevada.

56. V. D. Mishra, A. Singh, L. Verma, and G. Rajesh, 2022, “Ballistic Study of Shear Thickening Fluid Impregnated Unidirectional Ultra-High Molecular Density Polyethylene Fabric,” Recent Advances in Applied Mechanics, 125-134.

55. Velari Yogeshkumar, R. V. Reji, P. A. Ramakrishna, and G Rajesh, 2021, "Enhancement of Combustion of a Solid Fuel Ramjet for its Application in an Artillery Shell," 12th International Symposium on Special Topics in Chemical Propulsion & Energetic Materials (ISICP-12), ISICP-12

54. Vinoth P, Thara Reshma I V, and G Rajesh, 2020, "Numerical Simulation of Over Expanded Jets in Weak Shock Reflection Domain," 6th National Symposium on Shockwaves, February 26-28, IITM, Chennai, India.

53. T Yousaf Saidalavi, G Rajesh, P K Pandey, S Kaur, and A.K. Vishwakarma 2020, "Blast Effect on the Trajectory of Artillery Shell," 6th National Symposium on Shockwaves, February 26-28, IITM, Chennai, India.

52. Diviaharshavardini R C, Arul Prakash K, and G Rajesh, 2020, "Parametric Analysis on Design of Hypersonic Ludwieg Tube For Mach 6 Flow," 6th National Symposium on Shockwaves, February 26-28, IITM, Chennai, India.

51. Rohtash Goyal, A. Sameen, T. Jayachandran, and G Rajesh, 2020, "Numerical Investigation of Regular and Mach Reflection of Oblique Shock Waves in UnsteadyFlows," 6th National Symposium on Shockwaves, February 26-28, IITM, Chennai, India.

50. Sivaprasad G, Arun Kumar R, and G Rajesh, 2020, "Investigation of Change in Bifurcation Characteristic During the Flow Evolution in Backward Facing Step Using DMD and LDV," 6th National Symposium on Shockwaves, February 26-28, IITM, Chennai, India.

49. P N Verma, M V Suryawanshi, K D Dhote, Satwinder Sigh, V K Dixit, H K Gogoi, M K Singh, G Rajesh, T Y Saidalavi, 2019, "Implosion Driven Hypervelocity Fragment Launcher: Experiments and Simulations," 12th International High Energy Materials Conference & Exhibit, December, IITM, Chennai, India.

48. Sreelal M R and G Rajesh , 2019, “Analytical and Experimental Studies on Sabot Separation in Intermediate Ballistic Regimes,” The 31st International Symposium on Ballistics, November Hyderabad, India.

47. Nitesh K. Sinha, G Rajesh, and Badal Modi, 2019, "Viscous Corrections for Hypersonic Air Intake Using CFD Simulations," AIAA 2019-3594. DOI

46. I V Thara Reshma, P Vinoth, G Rajesh, and G Ben-Dor, 2019, "Study on Normal Shock Moving over a Smooth Downward Ramp," 32nd International Symposium on Shockwaves, July, National University of Singapore, Singapore.

45. R Arun Kumar, J Gopalan, G Rajesh, and K Takayama, 2019, "An Experimental Study on Refracted Shocks and its Interaction with Underwater Bodies" 32nd International Symposium on Shockwaves, July, National University of Singapore, Singapore.

44. G Sivaprasad, R Ramprakash, G Rajesh, and R Arun Kumar, 2019, "Starting Shock Swallowing in a Supersonic Wind Tunnel: A Shock Transition Problem?," 32nd International Symposium on Shockwaves, July, National University of Singapore, Singapore.

43. R C DiviaHarshaVardini, K Arul Prakash, and G Rajesh, 2019, "Improved Transition Model for Hypersonic Boundary Layers," 32nd International Symposium on Shockwaves, July, National University of Singapore, Singapore.

42. I V Thara Reshma, Shobhan Roy, and G Rajesh, 2019, "A Study on the Effect of Wedge Position on Mach Stem Height in Steady Supersonic Flows," 32nd International Symposium on Shockwaves, July, National University of Singapore, Singapore.

41. Ijaz Ahamed and G Rajesh, 2019, "FSS- RSS Transition In Thrust Optimized Parabolic (TOP) Nozzles during Start-Up and Shut Down," 14th International Symposium on Experimental Computational Aerothermodynamics of Internal Flows, July, Gdansk, Poland.

40. Sreelal M R and G Rajesh, 2018, "Performance Analysis of Rapid Separation Sabot on an FSAPDS Projectile ," 7th Asian Joint Workshop on Thermal and Fluid Sciences, November, Thiruvananthapuram, Kerala.

39. Sivaprasad G, Arun Kumar R, G Rajesh and Kim H D, 2018, "A Comparitive Study on the Start-up Process in Single Stage and Two Stage Vacuum Ejectors," 7th Asian Joint Workshop on Thermal and Fluid Sciences, November, Thiruvananthapuram, Kerala.

38. I V Thara Reshma, Rohit Jejani, and G Rajesh, 2018, "Some Interesting Shockwave Transitions in Weak Shock Reflection Domain," 32nd National Convention of Aerospace Engineers, BIT Mersa, Ranchi, India.

37. Sreelal M R and G Rajesh, 2018, "A Study on Shock Interactions in A Sabot Separation Process," 25th International Symposium on Military Aspects of Blast and Shock, September, The Hague, The Netherlands.

36. Yousaf Saidalavi, G Rajesh and Gabi Ben-Dor, 2018, "A Study of Shock Interactions Inside A Helmet Under Blast Loading," 25th International Symposium on Military Aspects of Blast and Shock, September, The Hague, The Netherlands.

35. Arun Kumar R and G Rajesh, 2018, "Shock Wave Diffraction Over Under Water Bodies," 25th International Symposium on Military Aspects of Blast and Shock, September, The Hague, The Netherlands.

34. Shobhan Roy and G Rajesh, 2018, "An Analytical Model for Asymmetric Mach Reflection Confguration in 2-D Steady Flows," 23rd International Shock Interaction Symposium, July, Kruger National Park, South Africa.

33. Vinoth P, Sushmitha J and G Rajesh, 2018, "Analytical and Numerical Predictions of Mach Stem height in Overexpanded and Underexpanded 2-D Jets," 23rd International Shock Interaction Symposium, July, Kruger National Park, South Africa.

32. Sivaprasad G, Arun Kumar R and G Rajesh, 2018, "Flow Visualization of 3-D shock Transformations in Cylindrical Vacuum Ejectors," 23rd International Shock Interaction Symposium, July, Kruger National Park, South Africa.

31. Arun Kumar R and G Rajesh, 2018, "A Study on the Reflection and Refraction of Blast Wave Sliding Over an Air-Water Interface," 23rd International Shock Interaction Symposium, July, Kruger National Park, South Africa.

30. Vinoth P and G Rajesh, 2018, "Prediction of Mach Stem Height in Overexpanded Jets," 5th National Symposium on Shockwaves," 5th National Symposium on Shockwaves, February 26-28, TBRL Chandigarh. (Best Poster Award)

29. Anilkumar Pasam and G Rajesh, 2018, "A Simpler Criterion for Detachment Condition in Double Wedge Shock Reflections," 5th National Symposium on Shockwaves, February 26-28, TBRL Chandigarh.

28. Arun Kumar R and G Rajesh, 2018, "An Experimental Study on the Blastwave Propagation over an Air-Water Interface," 5th National Symposium on Shockwaves, February 26-28, TBRL Chandigarh.

27. Arun Kumar R and G Rajesh, 2017, "Upstream Pressure Induced MR-RR Shock Transitions," 31st International Symposium on Shockwaves, July 9-14, Nagoya University, Japan.

26. Athira C M and G Rajesh, 2017, "Experimental study on Configuration Effects of Supersonic Projectiles in Transitional Ballistic Regimes," 31st International Symposium on Shockwaves, July 9-14, Nagoya University, Japan.

25. Shobhan Roy and G Rajesh, 2017, "Analytical Prediction of Mach Stem Height for Asymmetric Wedge Reflection in 2-D Steady Flows," 31st International Symposium on Shockwaves, July 9-14, Nagoya University, Japan.

24. K M M Rafi, B A H Fahd, M Deepu, and G Rajesh, 2017, "Experimental and Numerical Studies on Plume Structures of Micro-Nozzles Operating at High Vacuum Conditions," 31st International Symposium on Shockwaves, July 9-14, Nagoya University, Japan.

23. Ijaz Mohamed and G Rajesh, 2017, "Shock interactions in Thrust Optimized Parabolic (TOP) Nozzles during Start-Up and Shut Down," 31st International Symposium on Shockwaves, July 9-14, Nagoya University, Japan.

22. Athira C M and G Rajesh, 2016, "Experimental Study of Projectile -Blast Flow Field Interactions in Transitional Ballistic Regime," 24th International Symposium on Military Aspects of Blast and Shock, September, Halifax, Canada.

21. Badrinarayanan A S and G Rajesh, 2016, "Computational Simulation of Shock Interactions in Supersonic Projectile Launch," 22nd International Shock Interaction Symposium, July, University of Glasgow, United Kingdom.

20. Dheepak N Khatri, Pasam Anil Kumar, G Rajesh, and Santanu Ghosh, 2016, "Hysteresis Phenomenon in reflection of Asymmetric Shock Waves," 22nd International Shock Interaction Symposium, July, University of Glasgow, United Kingdom.

19. Arun Kumar R and G Rajesh, 2016, "Shock Transformations in Vacuum Ejectors," 22nd International Shock Interaction Symposium, July, University of Glasgow, United Kingdom.

18. Arun S, Arun Kumar R, Sameen A, G Rajesh, and Balaji Srinivasan, 2016, "Numerical Investigation of Initial Transients on The Flow Field In A Vacuum Ejector," 4th National Symposium of Shockwaves, February, Karunya Institute of Technology, Coimbatore, India.

17. Arun Kumar R and G Rajesh, 2016, "Diffuser Flow Characteristics During Vacuum Ejector-Diffuser Start-Up," 4th National Symposium of Shockwaves, February, Karunya Institute of Technology, Coimbatore, India.

16. Arun Kumar R and G Rajesh, 2015, "A Study on unsteady shear layer-shock Interaction in a vacuum ejector-diffuser system ," 30th International Symposium on Shockwaves, July, Ben-Gurion, Israel.

15. Vinod Yeldho Baby, and G Rajesh, 2015, "Experimental Study on the Interaction of Under Expanded Jets in Rarefied Flow Regimes," 30th International Symposium on Shockwaves, July, Ben-Gurion, Israel.

14. Arun Kumar R, G Rajesh, and Kim H D, 2015, "Flow characteristics of vacuum ejectors during start-up," 12th International Symposium on Experimental and Computational Aerothermodynamics of Internal Flows, July, Lerici, Italy.

13. G Rajesh, T. Hashimoto, and H. D. Kim, 2012, " CFD Analysis of the Compressible Flow in a Vortex Cup," Proceedings of 4th Asian Joint Workshop on Thermophysics and Fluid Science, October, Busan, Korea.

12. C. K. Muthukumaran, G Rajesh, H. D. Kim, 2012 , “A study on the unsteady aerodynamics of projectiles in overtaking blast ﬂow ﬁelds,” 9th International Conference on Heat transfer, Fluid Mechanics and Thermodynamics, Italy, Malta.

11. Anand Raj Hariharan, S. Anil lal, Z. A. Samitha, G Rajesh, and P. Balachandran, 2010, “Thermal Mixing Analysis Of Three Lobed Clover Nozzle” 1st International Symposium on Mechanics, Materials and Management, January, College of Engg., Trivandrum, Kerala, India.

10. Fazil Mohammed, S. Anil lal, Z. A. Samitha, G Rajesh, and P. Balachandran, 2009, “A Parametric Study for the Optimization of a Supersonic Ejector,” The 20th International Symposium on Transport Phenomena, July, Canada

9. Anand Raj Hariharan, Z. A. Samitha, S. Anil lal, G Rajesh, and P. Balachandran, 2009 ,“Numerical Analysis of Thermal Mixing with Clover nozzle,” The 20th International Symposium on Transport Phenomena, July, Canada

8. G Rajesh, and H. D. Kim, “A Study on the Interior Ballistics of a Two-Stage Light-Gas Gun,” 2008, 2nd Asian Joint Workshop on Thermophysics and Fluid Science, May, Luoyang, China

7. G Rajesh, Suryakant Nagdewe, H. D. Kim, and T. Setoguchi, 2008, “Supersonic and Subsonic Projectile Overtaking Problems in Muzzle Gun Applications,” 4th Asian Joint Conference on Propulsion and Power, March, Daejon, Korea

6. G Rajesh, H. D. Kim, S. Matsuo, T. Setoguchi, and M. Deepu, 2008, “Computational Analysis of the Transient Flows in an Ejector-Diffuser System,” 12th Asian Congress on Fluid Mechanics, August, Daejon, Korea

5. G Rajesh, H. D. Kim, and Y. K. Lee, “Computational Study of the Operating Processes of a Ballistic Range,” 2008, 12th Asian Congress on Fluid Mechanics, August, Daejon, Korea

4. Rajesh, G. Pillai, H. G. Kang, H. D. Kim, and Suryakant Nagdewe, 2007 “Computational Study of the Unsteady Aerodynamics of the Projectile Overtaking a Moving Shockwave,” 7th Asian Computational Fluid Dynamics, November, Bangalore, India.

3. G Rajesh, R. Mishra, H. G. Kang, and H. D. Kim, 2007, “Computational Study of the Compressible Flow Driven by a Piston in the Ballistic Range,” 8th International Symposium on Experimental and Computational Aerothermodynamics of Internal Flows, July, Lyon, France

2. G Rajesh, H. D. Kim, T. Setoguchi, and S. Matsuo, 2006, “Optimization Study of a Coanda Ejector,” 1st Asian Joint workshop on Thermophysics and Fluid Sciences, June, Qufu, China

1. G Rajesh, H. G. Kang, H. D. Kim, and T. Setoguchi, 2006, “Theoretical and Computational Studies on Ballistic Range Performance,” 1st Asian Joint workshop on Thermophysics and Fluid Sciences, June, Qufu, China

Invited Talks

Shock Propagation and Transition on Air And Air-Water Interfaces , 7th Asian Joint Workshop on Thermal and Fluid Sciences, Thiruvananthapuram, Kerala, November 2018

Shock Reflections in Compressible Open jets, Vellore Institute of Technology, Vellore, March 2018

Shock Wave Technology: Future Prospects in Agri-Food sector, International Conference on Food Processing and Agribusiness-“Emerging Trends,” Indian Institute of Plantation Management, Bangalore, January 2018

Time resolved schlieren and shadowgraph techniques for high-speed flows, Rajalekshmi Engineering College, July 2017

High-Speed Imaging Techniques, College of Engineering Adoor, KUSAT, March 2017

Transitional Ballistics of Supersonic Projectiles, International Conference on Recent Advances in Aerospace Engineering, Karunya University, March 2017

Flow Visualization Techniques, Rajalekshmi Engineering College, August 2016

Mach Reflection Phenomenon in Open Jets, College of Engineering Adoor, KUSAT, January 2016

Transitional Ballistics, NIT Suratkal, September 2015

Courses Offered

IIT Madras

Theory of Interior & Intermediate Ballistics (Graduate)

Fluid Mechanics (Undergraduate)

Aerodynamics and Aircraft Performance (Graduate)

Gas Dynamics (Undergraduate)

Compressible Fluid Flow (Graduate)

Experimental Aerodynamics (Undergraduate)

Aerodynamic Design of Aircrafts (Graduate & Undergraduate)

Shockwave Dynamics (Graduate & Undergraduate)

Experimental Methods in Aero/Gas Dynamics (Graduate)

Low-speed Lab (Undergraduate)

AeroLab I & II (Undergraduate)

Laboratory I (Graduate)

Keimyung University, South Korea

Fluid Mechanics

Thermodynamics

Introduction to Automotive Engineering

IIST, Thiruvananthapuram

Gas Dynamics

Aerodynamics

Thermodynamics

Engineering Mechanics

Aerodynamics Lab

People

Vinoth P

PhD Scholar

Research Topic: Unsteady shock Reflections in open jets and Magnetohydrodynamic (MHD) flows

Divia Harshavardini S

PhD Scholar (Jointly with Dr. Arul Prakash K)

Research Topic: Hypersonic Boundary Layer Transition

Sivaprasad G

PhD Scholar (PMR Fellow)

Research Topic: Bistability in Suddenly Expanding High-Speed Confined Jets

Nitesh Kumar Sinha

PhD Scholar (SCL, ISRO)

Research Topic: Micro-Nozzle Flows

Shubham K Vyas

PhD Scholar

Research Topic: Interior Ballistic Simulations of High Explosive Shells

Anbu Serene Raj C

PhD Scholar (Jointly with Dr. A Sameen)

Research Topic: Richtmyer–Meshkov instability in Density Stratified Media

Vinod Yeldho Baby

PhD Scholar (QIP)

Research Topic: Mach number Variation Induced Shock Transitions

Vishnu Prasad S

PhD Scholar

Research Topic: Expansion Fan Diffraction over Bodies

Past

Dr. Thara Reshma I V (2022)

Thesis: Shock Wave Reflections and Transitions in the Weak Shock Reflection Domain

Assistant Professor, Manipal Institute of Technology

Dr. Athira C M - PhD (2021)

Thesis: Aerodynamics of High-Speed Projectiles in the Intermediate Ballistic Regimes

Senior Project Officer, Ballistic and High-Speed Flow Lab, IIT Madras

Dr. Sreelal M R - PhD (2021)

Thesis: Investigation on Sabot Separation Phenomenon & Design of Lift Separation Sabots for Kinetic Energy Projectiles

Senior Project Officer, Ballistic and High-Speed Flow Lab, IIT Madras

Dr. Arun Kumar R - PhD (2018)

Thesis: Transient Flow Characteristics in High-Speed Confined Jets

Assistant Professor, IIT Jodhpur

Dr. Arun S- PhD (2019)

Thesis: Computations of High-Speed Mixing layers (Jointly with Dr. A Sameen)

Shobhan Roy - MS (2019)

(Jointly with Dr. Santanu Ghosh)

Thesis: Shock-Boundary Layer Interaction on Porous Surafces

Ijaz Ahamed - MS (2021)

Thesis: Shock Interactions in Thrust Optimised Parabolic (TOP) Nozzles during Start-Up and Shut-Down Transient

Scientist/Engineer, LPSC, ISRO

Dual Degree & M.Tech

1. Anil Kumar Pasam - Regular Reflection-Mach Reflection transitions in double wedge geometry (2017)

2. J. Jayasilan - Design and Computational Analysis of Ludwieg Tube (2017)

3. Ravi Prakash - Design of Dual Bell Nozzle (2016)

4. Vinod Yeldho Baby - Experimental Study on Interactions of Under Expanded Jets in the Rarefied Flow Regimes (2015)

5. Badrinarayanan A S - Computational Simulation of Launch Disturbances of Kinetic Energy Projectiles in the Intermediate Ballistic Regime (2015)

6. Keerthi Balakumar - An Experimental Study of Projectile Blast Flow Fields in Transitional Ballistic Regimes (2015)

2005 - 2008

Ph.D

Mechanical Engineering

School of Mechanical Engineering
Andong National University
South Korea

1997 - 1999

Master of Technology

Mechanical Engineering

College of Engineering Trivandrum
University of Kerala

1990 - 1994

Bachelor of Technology

Mechanical Engineering

TKM College of Engineering
University of Kerela

2021 - present

Professor

Dept. of Aerospace Engineering

IIT Madras
Chennai

2013 - 2021

Associate Professor

Dept. of Aerospace Engineering

IIT Madras
Chennai

2012 - 2013

Assistant Professor

Dept. of Mechanical and Automotive Engineering

Keimyung University
South Korea

2008 - 2012

Assistant Professor

Dept. of Aerospace Engineering

IIST, Valiamala
Thiruvananthapuram

2003 - 2008

Lecturer

Mechanical Engineering

Govt. Engineering College
Kerala

2001 - 2003

Scientist/Engineer

LPSC, ISRO

Valiamala
Thiruvananthapuram
Kerala

Aero-ballistic Range

The aero-ballistic range is used to accelerate projectiles of various configurations accelerated upto supersonic Mach numbers. The aero-ballictis range consists of a high pressure tube (HPT), a pump tube(PT) and a launch tube (LT). The HPT and PT are separated by thin plastic diaphragms (OHP sheet), and the PT and the LT are separated by a scored aluminium diaphrgam of thickness 0.9mm to 1.2mm. When the high pressure tube is given a pressure of 10 - 20 bar, the plastic diaphragm breaks which pushes the piston in the PT and the piston develops very high pressures (~200-300 bar) in the pump tube, and the aluminum diphragm is broken. LT flow is initiated and the projectile kept in the LT is accelerated to very high velocities. When the projectile comes out of the tube, the flow field is captured using time resolved schlieren or shadowgraph techniques.

Typical tests that are conducted in the aero-ballistic range are studies on shock-shock interactions, projectile-flow field interactions, unsteady aerodynamics of supersonic and transonic projectiles in transitional ballistic regimes, blast impact of steel and aluminium structures, etc.

Open Jet Facility

The open jet facility is fed from a 36 cubic meter, 10 bar reservoir. The stagnation chamber pressure is controlled by two pressure regulating valves (PRV) connected parallelly to acheive a maximum flow rate of 2kg/s. Typical tests that are conducted in this facility include, open jet studies in nozzle flow, ejector studies, etc.

High-speed imaging facilities

Schlieren system

The schlieren system consists of two no.s of 300mm diameter, 2000 mm focal length parabolic mirrors, a Newport 100W halogen light source, 150mm diameter, 450 mm focal length bi-convex lens and two high-speed cameras (IX-726 and Photron SA-4) with 26000 FPS and 3600 FPS at 1 MP, and a minimum exposure time of 259 ns, (Max. FPS: 1 Million) and 1 micro sec (Max. FPS: 0.6 million) repectively

G Rajesh

Research Interests : Experimental Aerodynamics - High Speed Flows & Shockwave Dynamics

Current Research

Future Plans

Funded Projects

Journal Articles

National and International Conferences

Invited Talks

Courses Offered

People

Vinoth P

PhD Scholar

Research Topic: Unsteady shock Reflections in open jets and Magnetohydrodynamic (MHD) flows

Divia Harshavardini S

PhD Scholar (Jointly with Dr. Arul Prakash K)

Research Topic: Hypersonic Boundary Layer Transition

Sivaprasad G

PhD Scholar (PMR Fellow)

Research Topic: Bistability in Suddenly Expanding High-Speed Confined Jets

Nitesh Kumar Sinha

PhD Scholar (SCL, ISRO)

Research Topic: Micro-Nozzle Flows

Shubham K Vyas

PhD Scholar

Research Topic: Interior Ballistic Simulations of High Explosive Shells

Anbu Serene Raj C

PhD Scholar (Jointly with Dr. A Sameen)

Research Topic: Richtmyer–Meshkov instability in Density Stratified Media

Vinod Yeldho Baby

PhD Scholar (QIP)

Research Topic: Mach number Variation Induced Shock Transitions

Vishnu Prasad S

PhD Scholar

Research Topic: Expansion Fan Diffraction over Bodies

Past

Dr. Thara Reshma I V (2022)

Thesis: Shock Wave Reflections and Transitions in the Weak Shock Reflection Domain

Assistant Professor, Manipal Institute of Technology

Dr. Athira C M - PhD (2021)

Thesis: Aerodynamics of High-Speed Projectiles in the Intermediate Ballistic Regimes

Senior Project Officer, Ballistic and High-Speed Flow Lab, IIT Madras

Dr. Sreelal M R - PhD (2021)

Thesis: Investigation on Sabot Separation Phenomenon & Design of Lift Separation Sabots for Kinetic Energy Projectiles

Senior Project Officer, Ballistic and High-Speed Flow Lab, IIT Madras

Dr. Arun Kumar R - PhD (2018)

Thesis: Transient Flow Characteristics in High-Speed Confined Jets

Assistant Professor, IIT Jodhpur

Dr. Arun S- PhD (2019)

Thesis: Computations of High-Speed Mixing layers (Jointly with Dr. A Sameen)

Shobhan Roy - MS (2019)

(Jointly with Dr. Santanu Ghosh)

Thesis: Shock-Boundary Layer Interaction on Porous Surafces

Ijaz Ahamed - MS (2021)

Thesis: Shock Interactions in Thrust Optimised Parabolic (TOP) Nozzles during Start-Up and Shut-Down Transient

Scientist/Engineer, LPSC, ISRO

Dual Degree & M.Tech

Aero-ballistic Range

Open Jet Facility

High-speed imaging facilities

Schlieren system

Some results