Abstract
The propagation of a normal shock wave along a coupled convex–concave surface of equal radii has been analysed experimentally and numerically in this study. The experimental and numerical studies were conducted using a similar geometry as of that used by Ram et al. (J. Fluid Mech., vol. 768, 2015, pp. 219–239) for studying the shock wave transition from regular reflection to Mach reflection. Many interesting flow features such as shock wave transitions over the ramp, characteristics of the induced flow behind the shock wave and the development of a stationary separation shock wave have been observed in the study. The numerical results are validated with experimental data. While the shock wave transitions over the ramp are found to depend mainly on the ramp geometry, the characteristics of the stationary shock wave and the flow separation in the concave region of the ramp surface have been found to vary with the shock wave Mach numbers.
Highlights
There have been a lot of analytical, experimental and numerical studies on shock wave reflections and transitions in the steady, pseudo-steady and unsteady frameworks over many years to understand the characteristic changes in the flow field (Ben-Dor 2007)
During the unsteady downward movement of a planar shock wave over the ramp, the changes in the structure and characteristics of the shock wave, the nature of the flow developed behind the moving shock wave and other associated flow structures in the domain were mainly investigated in this study
0 0.03 0.04 0.05 0.06 0.07 0.08 x (m) the Mach stem grows nonlinearly as the shock wave travels in the planar section of the ramp
Summary
There have been a lot of analytical, experimental and numerical studies on shock wave reflections and transitions in the steady, pseudo-steady and unsteady frameworks over many years to understand the characteristic changes in the flow field (Ben-Dor 2007). The RR → MR transition along with the rate of growth of the Mach stem over convex surfaces was further studied by Geva, Ram & Sadot (2018) using high resolution experiments and computation They observed that the shock wave transition in unsteady flows is influenced by the rotation of the reflected shock wave about the point of reflection, which makes it different from the pseudo-steady transition. Ram, Geva & Sadot (2015) carried out a similar experimental study on the RR → MR transition on the convex surface followed by MR → RR transition on the concave surface using a coupled convex–concave geometry Both these studies investigated the non-stationary shock wave transitions when a planar shock wave traverses up a coupled concave–convex and a convex–concave surface of equal radii. The effect of convex and concave geometries on the structure and transition of the shock wave during its motion, and the nature of the flow structures behind the shock wave are investigated in this study
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
