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ARTICLE

The Effect of the Gap Ratio on the Flow and Heat Transfer over a Bluff Body in Near-Wall Conditions

Shaohua Zhai¹, Guannan Xi^2,*

1 School of Mechanical Engineering, Nantong University, Nantong, 226019, China
2 School of Mechanical Engineering, Nantong Institute of Technology, Nantong, 226019, China

* Corresponding Author: Guannan Xi. Email:

(This article belongs to this Special Issue: Recent Advances in Fluid Mechanics and Thermal Sciences)

Fluid Dynamics & Materials Processing 2022, 18(1), 109-130. https://doi.org/10.32604/fdmp.2022.018186

Received 06 July 2021; Accepted 20 August 2021; Issue published 10 November 2021

Abstract

In order to study the effect of different gap ratios on the thermofluid-dynamic field around a bluff body located in proximity to a heated wall, a series of experiments and numerical simulations have been conducted. The former were carried out using an open circulating water tank experimental platform and a single cylinder and square column as geometrical models (their characteristic length being D). The latter were based on the well-known SIMPLE algorithm for incompressible flow. The results show that the gap ratio is an important factor affecting the wake characteristics of near-wall bluff bodies. When the gap ratio is small, the influence of the wall on the bluff body wake is large. With an increase in the gap extension, periodic vortex shedding is enabled and heat transfer is strengthened accordingly; in addition, the vortex shedding period is larger for the square column. The square column displays hysteresis compared with the cylinder at the same gap ratio (the critical gap ratio of cylinder is 0.2∼0.4, while that of square column is 0.4∼0.6).

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