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.
","abstract_html":"<p>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.</p>","abstract_has_math":false,"creators":["Snider, Jacob"],"institution":null,"degree_name":"Master of Aerospace Engineering","degree_level":"Thesis - ERAU Login Required","degree_discipline":"Aerospace Engineering","degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2023,"date_issued":"2023-04-01T07:00:00Z","date_published":"2023-04-01T07:00:00Z","updated_at":"2026-07-27T19:25:10Z","subjects":["hypersonic inlets","inlet performance","Aeronautical Vehicles","Propulsion and Power"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://commons.erau.edu/edt/750","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["Snider, Jacob"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.available","label":"Dc Date Available","values":["2119-05-10T07:00:00Z"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Aerospace Engineering"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Thesis - ERAU Login Required"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Master of Aerospace Engineering"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["hypersonic inlets","inlet performance","Aeronautical Vehicles","Propulsion and Power"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://commons.erau.edu/edt/750"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["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.
"]},{"key":"dc:title","label":"Title","values":["A Numerical Evaluation of Hypersonic Inward-Turning Inlets at Off-Design Conditions"]}]}],"canonical_facts":{"dc:creator":["Snider, Jacob"],"dc:date.available":["2119-05-10T07:00:00Z"],"dc:description.abstract":["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.
"],"dc:identifier":["https://commons.erau.edu/edt/750"],"dc:subject":["hypersonic inlets","inlet performance","Aeronautical Vehicles","Propulsion and Power"],"dc:title":["A Numerical Evaluation of Hypersonic Inward-Turning Inlets at Off-Design Conditions"],"thesis:degree_discipline":["Aerospace Engineering"],"thesis:degree_level":["Thesis - ERAU Login Required"],"thesis:degree_name":["Master of Aerospace Engineering"]},"updated_at":"2026-07-27T19:25:10Z"}