Design of Three-Dimensional Hypersonic Inlets with Rectangular-to-Elliptical Shape Transition

TLDR

The authors present a 3‑D hypersonic inlet design method that uses inviscid stream‑tracing to create a smooth rectangular‑to‑elliptical shape transition, incorporates highly swept leading edges and a notched cowl for fixed‑geometry operation, and applies viscous corrections with boundary‑layer separation checks to produce a modular inlet optimized for Mach 6.0. Compared with a classical 2‑D inlet, the 3‑D design demonstrates good inviscid performance below design point and its on‑design viscous performance aligns with that of an efficient scramjet inlet.

Abstract

A methodology has been devised for the design of three-dimensional hypersonic Inlets, This methodology makes extensive use of inviscid stream-tracing techniques to generate an inlet with smooth shape transition from a rectangular-like capture to an elliptical throat. Highly swept leading edges and a significantly notched cowl enable use of these inlets in fixed geometry configurations. The design procedure includes a three-dimensional viscous correction and uses established correlations to check for boundary-layer separation caused by shock wave interactions. Complete details of the design procedure are presented and the characteristics of a modular inlet with a design point of Mach 6.0 are examined. Comparison with a classical two-dimensional inlet optimized for maximum total pressure recovery indicates that these three-dimensional inlets demonstrate good inviscid performance even when operating well below the design point. An estimate of the on-design viscous performance corresponds with that of an efficient inlet for scramjet applications.