Shock wave effects on a turbulent flow

A parametric study is done to investigate the change in a turbulent flow field caused by the passage of a shock wave. Two parameters are studied: the initial turbulent kinetic energy and the shock wave strength or density jump. A random or turbulent flow field is initiated within a two‐dimensional box. Euler’s equations are then solved using a second‐order accurate Godunov shock capturing method to calculate the change in turbulent structure and flow field parameters caused by the passage of a shock wave through the turbulent field. Two fields were analyzed, a random density field and a random velocity field. The passage of a shock through the random density field caused density and pressure variations that compare very well with experiments. Results of the shock passage through the random velocity field show that the shock causes an amplification in the turbulent kinetic energy of about 2 on a per unit mass basis. Furthermore, the length scale of the turbulent field behind the shock is smaller than that in front of the shock. Energy weighted wave numbers increase by as much as 30%. This change in length scales seems to be in disagreement with some experiments which seem to show larger time scales and larger length scales behind a shock, but in agreement with another experiment. For both results, fields containing strong shocks or weak turbulent fields yield the largest change in flow parameters. The shock wave is also affected by the turbulent field. Increasing the initial turbulent kinetic energy caused a straight shock wave to evolve into a shock containing curves and wrinkles of a size similar to the length scale of the unshocked turbulent field. These curves and wrinkles can lead to the generation of additional flow field oscillations.