Numerical assessment of flow control capabilities of three dimensional woven wire mesh screens

摘要

Computational Fluid Dynamics (CFD) simulations of low turbulence fluid flow through three dimensional (3D) wire screens have been carried out within this research to gain more insight into the flow phenomenon through woven wire mesh screens. This paper presents a novel attempt at identifying and distinguishing between fluid flow regions upstream, downstream and within woven wire mesh screen apertures, highlighting regions of velocity changes, as well as regions of change in turbulence quantities. Mesh screens of this type have recently been proposed as noise reduction treatments for aircraft landing gear. Industry now requires low cost computational tools to enable early design phase simulations of mesh screen technologies. This research paper advances previous studies on laminar-flow modeled numerical simulations for woven wire screens by accounting for turbulence with the aid of a suitably selected turbulence model, therefore numerically identifying the nature of turbulence to be found within the wake of woven wire screens. The nature of fluid flow speed reductions from woven wire screens is highlighted and recommendations for suitable woven wire screen locations when applied for possible aerodynamic noise reduction treatments are made. CFD predicted flow loss coefficients are compared against NACA documented experiments and classical correlations of wire screen loss coefficients while downstream near-field turbulence decay values are compared to correlated turbulence intensity decay of mesh wire screens. 3D simulations are carried out for wire screens of open area ratios of beta = 49.38%, 51.84%, and 67.26%. Results of flow loss coefficients compared to experimental measured values were within error margins of +/- 1% for best cases, and +/- 8% for worst cases. Results of downstream fluid flow speed reductions from mesh wire screens were shown to correlate with screen solidity (1 - beta) to within U-min= (1 - beta)U-infinity. (C) 2019 Elsevier Masson SAS. All rights reserved.