Over An Shock Wave 25 Points Transonic Flow Is A Mixed Subsonic Supersonic Flow Where The Local Mach Number Is Near 1 (54.73 KiB) Viewed 36 times
Over An Shock Wave 25 Points Transonic Flow Is A Mixed Subsonic Supersonic Flow Where The Local Mach Number Is Near 2 (11.58 KiB) Viewed 36 times
over an Shock wave - (25 points) Transonic flow is a mixed subsonic-supersonic flow where the local Mach number is near one. A typical example is the flow over the wing of a high-speed subsonic transport, such as the Boeing 777. When the airplane is flying at a free-stream Mach number 0.8 <M< 1.0, there will be a pocket of locally supersonic flow over the wing. This pocket is terminated by a weak shock wave, as illustrated in the figure. Early numerical calculations of such transonic flows airfoil assumed the flow to be isentropic, hence ignoring the entropy increase and total pressure loss across the shock 0.8 CM < 1.0 wave. Assuming the shock wave in the figure is locally a normal shock, M<1 M<1 a) calculate the total pressure ratio and entropy increase across the shock for the given Mach values of the supersonic pocket in the following table: M 1.08 1. 12 1.16 1.2 Po2 Po 1 fjoule S2-S1 Ikg.K) ] -
b) comment on the appropriateness of the isentropic flow assumption (based on the Mach number limit) for the solution of transonic flows involving shocks of this nature.
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