Direct Numerical Simulation of Acoustic Disturbances in the Rectangular Test Section of a Hypersonic Wind Tunnel


Direct numerical simulations (DNS) of the full-scale rectangular nozzle of a hypersonic wind tunnel are conducted to study the acoustic freestream fluctuations radiating from turbulent boundary layers (TBLs) along the nozzle walls. The nozzle geometry and the flow conditions of the DNS match those of the NASA 20-Inch Mach 6 Tunnel, and the DNS has been completed for a domain without spanwise sidewall boundary conditions. The turbulent boundary layer parameters based on the DNS compare well with those derived from Reynolds Averaged Navier-Stokes (RANS) calculations as well as with the predictions based on Pate's correlation. A similarly good comparison is observed for both the Mach number distribution and the Reynold's stresses obtained from the DNS and RANS calculations, respectively. Various characteristics of the acoustic pressure fluctuations within the inviscid core of the nozzle flow are compared with those associated with a single flat plate at a similar freestream Mach number. The frequency spectrum and bulk propagation speeds match well between the nozzle and the flat plate, but the rms pressure fluctuation is higher for the nozzle configuration, likely due to the combined effect of acoustic radiation from the top and bottom walls. Spatial contours of the two-point correlation coefficient display elliptical tails with approximately equal but opposite angles corresponding to the preferred directionality of acoustic structures radiated from both walls. Future work will focus on DNS of the full nozzle configuration, including the effects of the nozzle side walls.

Meeting Name

48th AIAA Fluid Dynamics Conference, 2018 (2018: Jun. 25-29, Atlanta, GA)


Mechanical and Aerospace Engineering


Financial support for the work is being provided by NASA-EPSCoR Missouri and NASA Langley Research Center.

Keywords and Phrases

Aerodynamics; Atmospheric thermodynamics; Boundary layer flow; Direct numerical simulation; Hypersonic boundary layers; Mach number; NASA; Navier Stokes equations; Nozzles; Numerical models; Plates (structural components); Turbulence; Turbulent flow, Acoustic disturbances; Freestream mach number; Hypersonic wind tunnels; Mach-number distributions; Nozzle configuration; Reynolds averaged navier-stokes calculations; Turbulent boundary layers; Two-point correlation, Wind tunnels

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Document Type

Article - Conference proceedings

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