A Predictive Near-Wall Model For Large Eddy Simulations

Spectral analysis of the DNS data indicates that thin-layer asymptotics is a

promising approach to model the interactions between the near-wall layer and

the outer flow. For this approach an asymptotic analysis of the filtered

Navier-Stokes equations is pursued in the limit in which the horizontal filter

scale is large compared to the thickness of the wall layer.  It is shown in

this limit that the filtered velocities in the near-wall layer are

determined to zeroth order by filtered velocities at the boundary of the wall

layer. Further, the asymptotics suggest that there is a scaled universal

velocity profile in the near-wall region. The profile is evaluated

through analysis of DNS data from channel flow at Re_{\tau}=5200. The

resulting profile is used along with asymptotically relevant terms

to formulate a predictive near-wall model. This model is a PDE solved on the

boundary plane for the LES domain to represent the integrated effects of

the wall on the LES.  We present results from a coarse LES using this wall

model.