Abstract:

ESDU 81017 provides data for estimating the mean forces, pressures and moments induced by flow around a finite-length cylindrical structure of circular section. Data are presented in ESDU 80025 for two-dimensional flow conditions when the effects of flow around the free end (or ends) can be ignored, as with very long cylinders. The data in ESDU 81017 are in the form of correction factors to the two-dimensional values to account for (i) the effect of the free end (or ends) and (ii) the effect of shear flow. The main effects of Reynolds number, surface roughness and flow turbulence are included through the use of ESDU 80025. Simplified calculation sheets allow the application of the basic data to tapered structures and to structures with step changes in cylinder diameter. A method is also provided to allow the method of estimating the two-dimensional pressure distribution and flow field velocities in ESDU 80025 to be extended to finite-length cylinders in uniform or shear flow. The principal applications for the data lie in calculating the mean wind loading acting on ground-based structures such as stacks, towers, silos, storage tanks and chemical processing equipment.