The prediction of the drag on structural beams

The usage of hodograph, wake-source, and vortex lattice theoretical potential flow models for characterizing the flow over bluff bodies is discussed. The models are employed to describe the drag of two-dimensional bodies in terms of the wake and the irrotational components, which may feature a vortex street. The discussion is focused on calculations of the pressure distribution over the front face of I- and L-beam forms, which are important in the construction of buildings. The separation point occurs at the sharp edges, with a velocity that can be obtained by Bernoulli's equation. The hodograph method involves data on the velocity distribution at the boundaries, while the wake-source technique requires measurements of the position of the separation point on velocity. The vortex-lattice method involves assumptions of zero velocity on the surface of the body, in addition to a set of control (separation) points, between which individual vortices are shed. The hodograph and wake-source methods are demonstrated to be useful only for shapes that are amenable to transformations.