The microscale model MIMO: development and assessment

The numerical model MIMO is a three-dimensional model for simulating microscale wind flow and dispersion of pollutants in built-up areas. It solves the Reynolds averaged conservation equations for mass, momentum and energy. Additional transport equations for humidity, liquid water content and passive pollutants can be solved. The Reynolds stresses and turbulent fluxes of scalar quantities can be calculated by several linear and nonlinear turbulence models. A staggered grid arrangement is used and coordinate transformation is applied to allow non-equidistant meshsize in all three dimensions in order to achieve a high resolution near the ground and near obstacles. The model was validated for a variety of test cases and it was applied successfully to air pollution problems.