Validation of the discrete element roughness method for predicting heat transfer on rough surfaces

The Discrete Element Roughness Method (DERM) is evaluated as an engineering solution to the problem of convective heat transfer on rough surfaces. As part of the present work, DERM is incorporated into a general purpose compressible CFD code and explored as a way of modeling the sub-resolved roughness scales. In addition, DERM-model inputs are evaluated in detail and developed to represent sand-grain roughness (SGR). The results display good agreement in a number of validation cases. The overall results clearly indicate that DERM has potential to improve heat transfer predictions beyond the capability of SGR models, while only slightly increasing the computation time.