A 2-D numerical model of boundary-layer flow over single and multiple surface condition changes

Based on the 1-D planetary boundary layer model of Weng and Taylor with E – ℓ turbulence closure, a 2-D numerical model is developed to study the atmospheric boundary-layer flow over single or multiple changes in surface conditions. These changes can include surface roughness, thermal and moisture properties. A constant flux wall layer is used within which approximate forms for the velocity, temperature, moisture and turbulent kinetic energy profiles are obtained by analytic solution with the assumption of production equal to dissipation of turbulent kinetic energy. We also use a simple, analytic model dealing with the surface roughness change effects in neutral stratification based on the concept of an internal boundary layer. Model results for roughness changes are discussed and compared with other models and published field data.