Characterization of a Supersonic Inlet with Controlled Inflow Conditions
Abstract
Supersonic inlets constitute a critical component of high-speed propulsion systems. Inefficiencies in their performance have detrimental impact on the operation of the engine, including excessive drag, and unstart. The performance of inlets is highly sensitive to two specific sets of boundary conditions: (a) downstream effects determined by the succeeding engine component, and (b) upstream effects induced by boundary-layer development on the forebody, and angle of attack configurations. While the former has been extensively studied, particularly in the context of backpressure variations due to combustion instabilities, the latter is a relatively unexplored problem. In this study, we will address the impact of realistic variations in the inflow (upstream effects) on the performance of a supersonic inlet. Intellectual Merit: We adopt a joint experimental and computational analysis to characterize the performance of a supersonic mixed compression inlet in the presence of unsteady and inhomogenous inflow conditions. Experiments will be designed to benchmark the natural inflow evolution and inlet performance, followed by the manipulation of the incoming boundary layer in a controlled manner, to model in-flight scenarios. This will include variations in boundary layer thickness and fluctuating parameters, and angle of attack effects, that will be recreated using passive and active actuators. A detailed quantification of boundary layer properties and inlet performance will be enabled by an array of traditional and novel diagnostic tools, tailored for high-speed flows. The complementary computational effort will perform corresponding high fidelity simulations of the inlet aided by turbulence modeling and synthetic turbulence generators, to accurately recreate the experimental inflow conditions. The performance of the inlet will be evaluated using linear and nonlinear modal analyses, to identify key mechanisms that drive performance deviations, with the objective of designing efficient control techniques to mitigate these effects. The fundamental study on boundary layer development in the inlet will also provide insights into the applicability of wall-modeled computational approaches, that can enhance the viability of time-resolved simulations for inlet design. Broader Impacts: The proposed effort will generate insights into fundamental flow-mechanisms including transition and wall-bounded turbulence in non-equilibrium boundary layers, and shock-boundary-layer-interactions in duct-flows. This provides a first-principles-based understanding of variations in inlet performance, essential to the development of real-time actuators with high control authority. This integrated study will significantly leverage the established expertise of the investigators, especially in the areas of experimental aerodynamics and high-fidelity numerical simulations, while taking advantage of the existing facilities and computational resources. Consequently, the students engaged in this research and its outcomes will come from a unique, culturally diverse population. The results will be broadly disseminated through presentations at conferences, publications in peer-reviewed journals, and through the investigators’ active collaborations with scientists at defense research laboratories, especially those within the Air Force Research Laboratories.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Dec 10, 2021
- Source ID
- N000142212005
Entities
People
- S. Unnikrishnan
Organizations
- Florida State University
- Office of Naval Research
- United States Navy