Computational Study of the Aerodynamic Performance of Subsonic Scarf Inlets

Abstract

A computational study has been conducted to assess the aerodynamic performance of subsonic scarf inlets. The computations were performed using the WIND 3D Navier-Stokes CFD code. The objective of the study was to investigate the aerodynamic performance of scarf inlets wherein the circumferential extent, , over which the transition from the extended lower lip to the non-extended lip was the primary variable. Other inlet design variables include inlet internal lip thickness and the axial length of the lower lip extension. Inlet performance is computed at takeoff, cruise and static conditions. The results indicate a fundamental change in the nature of the lip flow separation characteristics at takeoff conditions as is reduced from 180 o to 67.5 o . The desire for separation-free performance at static and cruise conditions leads to restrictions on the range of inlet design variables.