The lift and drag coefficients of a spacer is

Here the eddy viscosity DMH-1 μt=ρa1kmaxa1ω;ΩF2. Equations for the turbulent kinetic energy, k, and the specific dissipation rate, ω, are of the formequation(5)∂ρk∂t+ui∂ρk∂xi=τij∂ui∂xj−β*ρωk+∂∂xjμ+σk1μt∂k∂xjequation(6)∂ρω∂t+ui∂ρω∂xi=γνtτij∂ui∂xj−βρω2+∂∂xjμ+σωμt∂ω∂xj+2ρ1−F1σω21ω∂k∂xj∂ω∂xj.
The parameters and constants in Eqs. (4), (5) and (6) are presented in Ref [12]. Here Ω is the vorticity magnitude, a1,β, β*, σk1, σω, σω2, and γ are closure coefficients, and F1, F2 are the blending functions. Details of the closure parameters can be found in Ref [12].
Fig. 1. Schematic of the flow geometry.Figure optionsDownload full-size imageDownload as PowerPoint slide
The local Sherwood number (Sh) is calculated fromequation(8)Sh=hmhD,hm=D∂c∂yy=hcb−cwwhere hm is the local mass transfer coefficient, cb is the bulk concentration.