An Example of the Calculation of the Three-Dimensional Turbulent Boundary Layer on a Tanker Model

Abstract

The cross flow profile in the three-dimensional turbulent boundary layer is discussed, and it is shown that it is more convenient to express the cross flow velocity as an explict function of the main flow velocity. Considering polynomials of different degrees, it is shown that the 3rd degree polynomial is better in representing the cross flow in the sence that it decreases the dependency of the calculated limiting streamline angle on the conditions at the boundary layer outer edge. The concept of the skew function, which gives the distribution of the velocity component normal to the wall shear stress is introduced, and it is shown that this function is not universal. Using the 3rd degree polynomial for the cross flow it is possible to represent the different trends of the available experimental results for the skew function. The boundary layer calculations are conducted for a tanker model using a two parameter cross flow profile and Johnston equation as the auxiliary equation for the cross flow. The results are in reasonable agreement with the experimental trend, although there are some points which still need more research.