In a Very-Large-Eddy Simulation (VLES), the filterwidth-wavenumber can be outside the inertial range, and simple subgrid models
have to be replaced by more complicated (‘RANS-like’) models which can describe the transport of the biggest eddies. One could
approach this by using a RANS model in these regions, and modify the lengthscale in the model for the LES-regions
[1–3]. The problem with these approaches is that these models are specifically calibrated for RANS computations, and therefore
not suitable to describe inertial range quantities. We investigated the construction of subgrid viscosity and transport equations
without any calibrated constants, but these are calculated directly form the Navier-Stokes equation by means of a Renormalization
Group (RG) procedure. This leads to filterwidth dependent transport equations and effective viscosity with the right limiting
behaviour (DNS and RANS limits).
Keywords very-large-eddy simulation - subgrid modellig - k-ɛ model