Date of Award

Spring 2023

Embargo Period


Access Type

Thesis - ERAU Login Required

Degree Name

Master of Aerospace Engineering


Aerospace Engineering

Committee Chair

William Engblom

First Committee Member

Eric Perrell

Second Committee Member

Reda Mankbadi

College Dean

James Gregory


The susceptibility of hypersonic, inward-turning inlets to performance losses at off-design conditions is explored. Axisymmetric, inward-turning inlets were designed for Mach 6, and the inlet performance was evaluated from computational fluid dynamics (CFD) simulations. These inlets were run at a range of Mach number (Mach 6 ± 1.5) and angle of attack (0◦ - 2.5 ◦ ) to investigate off-design performance. Inlet performance was characterized by the mass flow averaged total pressure recovery, Mach number, flow distortion, and absolute static pressure amplification at the end of the inlet and at the isolator outflow. Based on the off-design cases, unstart boundaries were estimated. The sensitivity to equilibrium vibrational thermodynamic effects was also evaluated. Grid-independent results were ensured using a systematic grid adaptation approach with relatively modest final mesh size. Axisymmetric inward-turning inlets are shown to be relatively insensitive to performance losses at Mach numbers near design conditions until sudden unstart is reached. Equilibrium vibrational thermodynamic effects are not found to have a significant impact of inlet performance. Inlets were found to be very sensitive to off-design angle of attack. Time-accurate simulations with flow time-dependent grid coarsening/refinement is necessary to more precisely determine the unstart boundary.

Available for download on Wednesday, May 10, 2119