Unsteady mixed convection in a horizontal channel with protruding heated blocks and a rectangular vortex promoter

Qinghua Wang, Yogesh Jaluria

Research output: Contribution to journalArticlepeer-review

21 Scopus citations


The objective of this research is to study the resonance oscillatory flow in a channel and the resulting effect on thermal transport, leading to cooling enhancement in electronic systems. The unsteady mixed convection through a horizontal channel with two isolated protruding blocks on the bottom wall has been studied numerically. For this geometry, at moderate Reynolds numbers, the flow is found to separate at the leading edge of the first block, and then reattach at the top surface of the second block. At a given Grashof number, when Re exceeds a critical value, vortex is shed only from the second block, and rolls over the bottom wall with its size decaying, while one or two recirculating cells are trapped in the groove. The base vortex shedding frequency is dependent on the buoyancy level Gr/Re2. The critical value of Re is much lower when perturbation is introduced by a rectangular or square promoter in the channel. The frequency and amplitude of perturbation are changed by adjusting the geometry of the promoter. An improved fluid exchange between the main flow and the recirculating cell occurs when the promoter is employed. The effects of frequency and perturbation amplitude on the flow and on the heat transfer are investigated. The study consists of three parts. The first studies the developing flow in the grooved channel; the second investigates the vortex shedding from a rectangular promoter confined in a smooth channel; and the last studies the effect of resonance by tuning the frequency of vortex shedding.

Original languageEnglish (US)
Pages (from-to)2113-2127
Number of pages15
JournalPhysics of Fluids
Issue number7
StatePublished - Jul 2002

All Science Journal Classification (ASJC) codes

  • Computational Mechanics
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering
  • Fluid Flow and Transfer Processes

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