Mach yoj
Lub wavefront ntawm ib tug series ntawm kev cuam tshuam propagating nyob rau hauv ib tug supersonic airflow los ntawm ib tug ruaj tsis muaj zog cuam tshuam qhov chaw. Qhov no tau pom los ntawm Austrian physicist thiab philosopher F. Mach thaum nws sim nrog supersonic projectiles nyob rau hauv lig 1880s thiab thaum ntxov 1990s.