0
research-article

Investigation of flow dynamics over transitional-type microcavity

[+] Author and Article Information
Paulius Vilkinis

Laboratory of Heat-Equipment Research and Testing, Lithuanian Energy Institute, Breslaujos str. 3 Kaunas, LT-44403, Lithuania
paulius.vilkinis@lei.lt

Nerijus Pedisius

Laboratory of Heat-Equipment Research and Testing, Lithuanian Energy Institute, Breslaujos str. 3 Kaunas, LT-44403, Lithuania
nerijus.pedisius@lei.lt

Mantas Valantinavicius

Laboratory of Heat-Equipment Research and Testing, Lithuanian Energy Institute, Breslaujos str. 3 Kaunas, LT-44403, Lithuania
mantas.valantinavicius@lei.lt

1Corresponding author.

ASME doi:10.1115/1.4039159 History: Received September 27, 2017; Revised January 04, 2018

Abstract

Flow over a transitional-type cavity in microchannels is studied using a microparticle image velocimetry system and commercially available computational fluid dynamics software in laminar, transitional, and turbulent flow regimes. According to experimental results, in the transitional-type cavity (L/h1 = 10) and under laminar flow in the channel, the recirculation zone behind the backward-facing step stretches linearly with ReDh until the reattachment point reaches the middle of the cavity at xr/L = (0.5 to 0.6). With further increase in ReDh, the forward-facing step lifts the reattaching flow from the bottom of the cavity and stagnant recirculation flow fills the entire space of the cavity. Flow reattachment to the bottom of the cavity is again observed only after transition to the turbulent flow regime in the channel. Reynolds averaged Navier-Stokes equations (RANS) and large eddy simulation results revealed changes in vortex topology, with the flow regime changing from laminar to turbulent. During the turbulent flow regime in the recirculation zone, periodically recurring vortex systems are formed. Experimental and computational results have a good qualitative agreement regarding the changes in the flow topology. However, the results of numerical simulations based on RANS equations and the RSM-BSL turbulence model, show that computed reattachment length values overestimate the experimentally obtained values. The RSM-BSL model underestimates the turbulent kinetic energy intensity, generated by flow separation phenomena, on the stage of transitional flow regime.

Copyright (c) 2018 by ASME
Your Session has timed out. Please sign back in to continue.

References

Figures

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In