Effect of numerics and laminar-turbulent transition on heat flux distribution simulation over a typical re-entry module

Highlights: • Numerical solver validated with two standard test cases. • Heat flux trend of scaled model computed numerically matches with measured prototype values. • Hence solver can be used to generate hea flux data bank for design of Thermal Protection Systems in launch vehicles, missiles, etc. • Numerical results oscillates as aspect ratio of grid increases. • The influence of order of reconstuction is found to decrease with mesh refinement. - Abstract: A series of numerical experiments are carried for a scaled version of a typical re-entry module for different altitudes to study the effect of numerics and laminar-turbulent transition on heat flux distribution. Studies are carried out using CUDA based second order accurate unstructured cell centred in-house N-S solver. The solver is validated using two standard test cases and subsequently used for the heat flux studies over a typical re-entry module. Laminar simulations are carried out for scaled model to reduce computational time since around 80 simulations are carried out to for 8 operating altitudes for which measured data is available for the full scale module. Variation of simulated and measured heat flux data matches with each other with reasonable and acceptable levels. To address the issue of laminar-turbulent transition on heat flux values, simulations are repeated with turbulent solver as well solver capable of capturing the transition. Heat flux simulations in high speed flows are highly sensitive to the order of accuracy of the flow solver and grid quality such as aspect ratio and grid stretching. To address these issues, several numerical experiments are carried out and results are presented.