Next Article in Journal
Elementary Flow Field Profiles of Micro-Swimmers in Weakly Anisotropic Nematic Fluids: Stokeslet, Stresslet, Rotlet and Source Flows
Next Article in Special Issue
On the Bias in the Danckwerts’ Plot Method for the Determination of the Gas–Liquid Mass-Transfer Coefficient and Interfacial Area
Previous Article in Journal / Special Issue
Characterization of Bubble Size Distributions within a Bubble Column
Article Menu

Export Article

Open AccessArticle
Fluids 2018, 3(1), 14; https://doi.org/10.3390/fluids3010014

Coherent Vortical Structures and Their Relation to Hot/Cold Spots in a Thermal Turbulent Channel Flow

School of Mechanical Engineering, Purdue University, 585 Purdue Mall, West Lafayette, IN 47907, USA
*
Author to whom correspondence should be addressed.
Received: 22 December 2017 / Revised: 31 January 2018 / Accepted: 4 February 2018 / Published: 8 February 2018
(This article belongs to the Special Issue Flow and Heat or Mass Transfer in the Chemical Process Industry)
View Full-Text   |   Download PDF [5515 KB, uploaded 8 February 2018]   |  

Abstract

Direct numerical simulations of a turbulent channel flow with a passive scalar at R e τ = 394 with blowing perturbations is carried out. The blowing is imposed through five spanwise jets located near the upstream end of the channel. Behind the blowing jets (about 1 D , where D is the jet diameter), we observe regions of reversed flow responsible for the high temperature region at the wall: hot spots that contribute to further heating of the wall. In between the jets, low pressure regions accelerate the flow, creating long, thin, streaky structures. These structures contribute to the high temperature region near the wall. At the far downstream of the jet (about 3 D ), flow instabilities (high shear) created by the blowing generate coherent vortical structures. These structures move hot fluid near the wall to the outer region of the channel; thereby, these are responsible for cooling of the wall. Thus, for engineering applications where cooling of the wall is necessary, it is critical to promote the generation of coherent structures near the wall. View Full-Text
Keywords: coherent structures; wall heat flux; flow control; blowing; channel flow; direct numerical simulations (DNS) coherent structures; wall heat flux; flow control; blowing; channel flow; direct numerical simulations (DNS)
Figures

Figure 1

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. (CC BY 4.0).

Share & Cite This Article

MDPI and ACS Style

Dharmarathne, S.; Pulletikurthi, V.; Castillo, L. Coherent Vortical Structures and Their Relation to Hot/Cold Spots in a Thermal Turbulent Channel Flow. Fluids 2018, 3, 14.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Metrics

Article Access Statistics

1

Comments

[Return to top]
Fluids EISSN 2311-5521 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top