An expression is obtained relating mass transfer, due to forced convection, to hydrodynamic conditions over the entire surface of a sphere. In the case of the forward stagnation point no experimental data are required for the hydrodynamic conditions. The relationship may also be applied to circular cylinders in cross flow.
Up to the point of separation of forward flow anestablishedmethod,employingpressuredistribution data, is suggested for the estimation of hydrodynamic conditions, whilst a method is developed for estimating the conditions over the area contined by the wake.
By simple analogy predictions may be made for heat transfer which are in good agreement with experimental data.
In the case of the forward stagnation point of a sphere(orcircularcylinderincrossflow) thenormal dimensionless forced convection transfer groups are shown to be independent of Reynolds number but the groups for the over-all or partial surfaces are shown to be dependent on Reynolds number, contrary to much popular opinion. No form of this dependency is suggested on account of its complexity but the observation explains the reason for various investigators obtaining differentconstants, for different ranges of Reynolds number, in the usual dimensionless expressions.