Direct numerical simulation of slender cones with variable nose bluntness based on graphics processing unit computation

Direct numerical simulation with up to 10×109 scale grid points based on graphics processing unit computation is carried out investigate the bluntness effect hypersonic boundary-layer transition over a slender cone zero angle of attack at Mach 6. Four cases nose radii 1, 10, 20, and 40 mm are conducted, corresponding Reynolds number radius varies from 1.0×104 4.0×105. Random disturbances broad spectrum frequencies wide range azimuthal wavenumbers were applied wall simulate caused by roughness. The results show that as tip increases, position gradually moves downstream increased region. For case 1 mm, flow entropy swallowing occur almost simultaneously, while for other cases, takes place earlier than swallowing. In consequence, disturbance amplitude upstream in much larger cases. To further study mechanism transition, frequency analysis out. It found all exhibit two characteristic within region, i.e., high extremely low frequency. Owing influence layer, significantly higher With increase radius, decreases gradually.