Interaction and acoustics of separated flows from a D-shaped bluff body

Guangyuan Huang, Ka Him Seid, Zhigang Yang, Randolph Chi Kin Leung

Research output: Journal article publicationJournal articleAcademic researchpeer-review

Abstract

Purpose: For flow around elongated bluff bodies, flow separations would occur over both leading and trailing edges. Interactions between these two separations can be established through acoustic perturbation. In this paper, the flow and the acoustic fields of a D-shaped bluff body (length-to-height ratio L/H = 3.64) are investigated at height-based Reynolds number Re = 23,000 by experimental and numerical methods. The purpose of this paper is to study the acoustic feedback in the interaction of these two separated flows. Design/methodology/approach: The flow field is measured by particle image velocimetry, hotwire velocimetry and surface oil flow visualization. The acoustic field is modeled in two dimensions by direct aeroacoustic simulation, which solves the compressible Navier–Stokes equations. The simulation is validated against the experimental results. Findings: Separations occur at both the leading and the trailing edges. The leading-edge separation point and the reattaching flow oscillate in accordance with the trailing-edge vortex shedding. Significant pressure waves are generated at the trailing edge by the vortex shedding rather than the leading-edge vortices. Pressure-based cross-correlation analysis is conducted to clarify the effect of the pressure waves on the leading-edge flow structures. Practical implications: The understanding of interactions of separated flows over elongated bluff bodies helps to predict aerodynamic drag, structural vibration and noise in engineering applications, such as the aerodynamics of buildings, bridges and road vehicles. Originality/value: This paper clarifies the influence of acoustic perturbations in the interaction of separated flows over a D-shaped bluff body. The contribution of the leading- and the trailing-edge vortex in generating acoustic perturbations is investigated as well.

Original languageEnglish
Pages (from-to)1186-1203
Number of pages18
JournalInternational Journal of Numerical Methods for Heat and Fluid Flow
Volume32
Issue number4
DOIs
Publication statusPublished - 28 Mar 2022

Keywords

  • D-shaped body
  • Flow-acoustic couplings
  • Separated flows

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Computer Science Applications
  • Applied Mathematics

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