Separation Dynamics: The View From the Wall

Abstract

Flow separation and reattachment have a profound impact on the performance of flight vehicles, yet are probed using only a small number of discrete wall sensors. As the flow crosses the onset of separation, the spectra of the incident disturbances change significantly. As a result, the accuracy of interpreting wall-pressure data is sensitive to sensor placement, whether the sensor is positioned upstream of the separation or within the reverse-flow region. This research investigates the challenges of flow estimation within a separated high-speed flow. The impact of separation on the accuracy of flow estimation from wall measurements is first quantified in a compression ramp configuration with a six-degree ramp angle. At free-stream Mach number M = 5.59, this configuration produces a sufficiently strong compression which leads to separation upstream of the corner and downstream reattachment on the ramp. An ensemble variational (EnVar) data assimilation technique is used to perform two flow estimations: the first is conducted with sensor observations taken upstream of the separation, and the second with sensor observations taken from within the separated region.

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Document Details

Document Type
Technical Report
Publication Date
May 30, 2024
Accession Number
AD1230470

Entities

People

  • Tamer A. Zaki

Organizations

  • Johns Hopkins University

Tags

Fields of Study

  • Physics

Readers

  • Aerodynamics.
  • Atmospheric Science / Meteorology, specifically Wind Wave Turbulence.
  • Combustion and Flow Dynamics.