Abstract:

ESDU 75005 gives curves calculated from the oblique shock relationships for air enabling the performance to be obtained in terms of pressure recovery, mass flow ratio, and pre-entry drag. The curves apply at zero incidence, but can be used at incidence by a method explained. An equation to correct the results for sidespillage is included. The data apply to design Mach numbers of 2 to 2.8 for freestream Mach numbers of 1.6 up to design, where design is the condition when both oblique shocks lie simultaneously on the lip. The range of ramp angles with freestream (at zero incidence) is up to 6 degrees for the first ramp and up to 22 degrees for the second. A convenient-to-use flowchart explains how the curves are applied and their use is illustrated for a practical worked example including the effect of matching engine demand.