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Fundamental Physics Experiments

Fundamental physics experiments increase our understanding of more complex problems and provide important data for improving and validating physical models.

Fundamental Inlet Bleed Experiments (FIBE)

Accurate prediction of bleed flow models relies heavily upon understanding how the bleed orifice flow coefficient changes based on operating conditions.

A series of fundamental inlet bleed experiments were conducted at NASA’s Glenn Research Center.  This work’s goals were to provide a comprehensive experimental database and a better understanding of how bleed systems can be improved through better modeling, alternate bleed configurations, and bleed placement within supersonic and hypersonic inlets.

The Phase I experiment obtained flow coefficient data for 90 and 20-degree single bleed holes.

The Phase II experiment obtained flow coefficient data for 21 configurations of a single bleed hole.  Interactions between the design parameters of hole diameter, hole inclination angle, and thickness-to-diameter and the interactions between the flow parameters of pressure ratio and Mach number upon the flow coefficient were examined, and a preliminary statistical model was developed.

Microramp/Microvane Flow Control

Two adjacent microramp flow devices showing the horseshoe, primary, and secondary vortices shed.
Schematic of microramp flow features. Credit: Hirt

A combination of experimental and numerical work has been conducted at NASA’s Glenn Research Center to determine the effectiveness of microramp and microvane flow control devices on shock-wave boundary-layer interaction.

Mixing Layer Experiments

Instantaneous velocity vector field for compressible mixing layer at convective Mach number of 0.185.
Experimental mixing layer results. Credit: Dutton

NASA has funded a series of compressible planar mixing layer experiments to obtain high-quality data for turbulence model validation.  This database is available to all.

Turbulent Heat Flux (THX) Thermal Mixing

Rendering of the THX II-V experimental configurations. THX II is a convergent axisymmetric nozzle. THX III is a round-to-square nozzle with an aft deck plate. The plate has a single large cooling hole. THX IV uses three patches of smaller grouped cooling holes. THX V is a convergent-divergent axisymmetric nozzle.
THX experimental configurations. Credit: Wernet

A number of benchmark turbulent heat transport experiments were performed at NASA’s Glenn Research Center.  Detailed measurements of velocity and temperature were obtained.  This data will be used to validate and improve turbulence models for thermal mixing flows.

The Phase I test investigated measurement techniques within a small-scale tunnel cooling flow configuration.

The Phase II test investigated thermal transport within a subsonic axisymmetric jet.

The Phase III test involved a single large injector cooling hole to study fundamental physics.

The Phase IV test involved three patches of smaller cooling holes in a staggered pattern representative of a realistic application.  This multi-hole configuration is the focus of the 2021 AIAA Propulsion Aerodynamic Workshop.

The Phase V test investigated the turbulent heat transport within a supersonic axisymmetric jet.

Axisymmetric Shock-Wave Boundary-Layer Interaction (SWBLI)

Three-dimensional and cross-section views of axisymmetric centerbody in a round wind tunnel. Oblique shock wave from the centerbody reflects off the tunnel walls.
3D and Cross-Section Views of Axisymmetric SWBLI experiment. Credit: Davis

Shock-wave boundary-layer interaction is prominent in supersonic inlets, yet high-quality validation data is difficult to find.  Documenting experiments performed in rectangular wind tunnels can be quite challenging due to the three-dimensional interaction that occurs in the corner regions.  To overcome this issue, an experiment was conducted at NASA’s Glenn Research Center using an axisymmetric configuration.  The data obtained will be used to improve numerical simulations further.

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