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Accession Number ADA564329
Title High Enthalpy Effects on Two Boundary Layer Disturbances in Supersonic and Hypersonic Flow.
Publication Date May 2012
Media Count 284p
Personal Author R. M. Wagnild
Abstract The fluid flow phenomenon of boundary layer transition is a complicated and difficult process to model and predict. The importance of the state of the boundary layer with regard to vehicle design cannot be understated. The high enthalpy environment in which high speed vehicles operate in further complicates the transition process by adding several more degrees of freedom. In this environment, the internal properties of the gas can stabilize or destabilize the boundary layer as well as modify the disturbances that cause transition. In the current work, the interaction of two types of disturbances with the high enthalpy flow environment are analyzed. The first is known as a second mode disturbance, which is acoustic in nature. The second type is known as a transient growth disturbance and is associated with flows behind roughness elements. Theoretical analyses, linear stability analyses, and computation fluid dynamics (CFD) are used to determine the ways in which these disturbances interact with the high enthalpy environment as well as the consequences of these interactions. First, acoustic wave are directly studied in order to gain a basic understanding of the response of second mode disturbances in the high enthalpy boundary layer. Next, this understanding is used in interpreting the results of several computations attempting to simulate the flow through a high enthalpy flow facility as well as experiments attempting to take advantage of the acoustic interaction with the high enthalpy environment. Because of the difficulty in modeling these experiments, direct simulations of acoustic waves in a hypersonic flow of a gas with molecular vibration are performed. Lastly, compressible transient growth disturbances are simulated using a linear optimal disturbance solver as well as a CFD solver.
Keywords Acoustic waves
Boundary layer transition
Compressible flow
Enthalpy
Flow rate
Fluid dynamics
Fluid flow
Hypersonic flow
Molecular vibration
Optimization
Supersonic flow
Theses

 
Source Agency Non Paid ADAS
NTIS Subject Category 46B - Fluid Mechanics
Corporate Author Minnesota Univ., Minneapolis.
Document Type Thesis
Title Note Doctoral thesis.
NTIS Issue Number 1302
Contract Number FA9550-04-1-0341 FA9550-10-1-0352

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