ABSTRACT

This chapter discusses boundary layers in these situations and try to determine theoretical values for the convective transport coefficients. The boundary layer in the confined space of a tube is much different from that found on a flat plate or over a cylinder or sphere. Flow over spherical objects has much in common with flow over cylinders. However, in the spherical case, the surface curves away from the bulk flow in two dimensions rather than in one. The best way to determine the friction factor and the heat and mass transfer coefficients for flow about a cylinder is by experimentation because no two cylinders have exactly the same roughness or shape. In flow over cylinders or spheres, the boundary layer separates from the surface and forms a wake behind the object. In flow within a tube or conduit, the boundary layer can grow only as large as the tube radius permits.