Velocity Measurements of Vortex Breakdown in an Enclosed Cylinder

Abstract

Experimental measurements were carried out of three-component velocity fields inside a cylindrical container. Flow was driven by the rotation of the top endwall disk. The purpose of the precision laser-Doppler velocimetry measurements was to describe the velocity characteristics pertinent to the vortex breakdown phenomenon. A turntable experimental apparatus was fabricated. Extensive laser-Doppler measurements, as well as flow visualizations, were made for the aspect ratio 1.50 and 2.50, and the Reynolds number ranges 0.99×103-2.20×103. The measured meridional velocities were found to be consistent with the prior visualization studies. The characteristic changes in swirling motions in the vicinity of vortex breakdown bubble are depicted. Detailed flow patterns near the rotating disk are constructed by using the experimental data.

Lattice Boltzmann simulation of lid-driven swirling flow in confined cylindrical cavity

“…Specifically, the values chosen are, (A) (1.5, 990), (B) (1.5, 1290) and (C) (2.5, 1010) respectively. These parameters correspond to the three cases experimentally investigated by Fujimura et al [14]. We carried out LB simulations on 97 · 97 · 73 (for the Cases A and B), and 97 · 97 · 121 (for the Case C) lattice grid points.…”

“…Sørenson [24] extended the study to reveal that the flow becomes highly asymmetric beyond a critical Re well within the unsteady flow regime. The visualization data obtained by Escudier [8] and others have been supported by recent, very accurate Laser Doppler Velocimetry measurements [14].…”

“…For this purpose, the LBE approach is taken to model the 3D dynamics of the bubble breakdown and the results are compared with well-documented experimental data [14] as well as conventional numerical solutions of N-S equations. In this work, we implement the currently practised multiple-relaxation time (MRT) model [30,31] of the LBM on the D3Q19 lattice.…”

“…This is an important generic problem investigated both experimentally [6][7][8][9][10][11][12][13][14] and computationally [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] by a number of researchers. Significance of this problem arises owing to the interesting flow-phenomena associated with the formation and subsequent breakdown of one or more recirculation bubbles centered on the cylindrical axis.…”

A Resolution Independent Solution for Confined Axisymmetric Vortex Breakdown Flow

“…For particular values of Re and h, experimental visualization is performed to crosscheck the numerical solution. The loci of stagnation points on the axis of rotation and the size of the vortex breakdown bubbles are measured from the experimentally realized flow field (13) . The benchmark solution presented in this report can be used to test solutions obtained by a newly developed numerical code.…”