Assessment of Dairy Cow Geometries in Computational Modeling

Abstract. A common practice in computational fluid dynamics (CFD) studies of dairy applications is to assume the cow to be represented by a simplified geometry, most commonly a sphere or cylinder. However, due to the increased computational power of modern computers, more detailed cow geometries can be integrated into CFD simulations. Realistic cow geometries have been used in CFD models to validate simplifying assumptions rather than utilizing the cow geometry in the model directly, due to the time and computing power required to evaluate them. However, with the increasing number of studies showing the feasibility of targeted cooling, systems which cool specific areas of the cow, cow models need to evolve to properly evaluate these systems. The geometry used in the CFD model must represent the targeted area (head, udder, etc.) but no guidelines exist as to how closely the cow geometry should represent the real cow. Therefore, our objective is to compare a realistic cow model to commonly used cow models: a spherical cow, a one cylinder cow, and a six cylinder cow. Specifically, the convective heat transfer coefficient of each of these models (both local and global) will be compared under different Reynold numbers. Expected results will indicate if utilizing a realistic geometry creates a significant difference in the heat transfer coefficients and determine the level of simplicity a modeler should use to maintain accuracy while keeping computational loads at a minimum.