Boundary Layer Calculation for Analysis and Design

Abstract

A simple, semiempirical method for calculating the laminar, transition, and turbulent boundary layer with arbitrary free stream pressure gradient is developed. Good correlation is obtained with data on general two dimensional turbulent flows, diffuser flows, and the cylinder in cross-flow. However only for the diffuser has the boundary layer flow been coupled with the potential core so that only the inlet conditions and geometry are required. In other cases the free stream velocity distribution must be known or calculable. Skin friction coefficient, momentum thickness Reynolds number, and free stream pressure gradient parameter correlation employs a simple lag theory. With the integral momentum equation the complete boundary layer parameters are obtained as functions of the distance along a surface.

Surface-friction coefficient in turbulent flow at a boundary layer

“…As is evident from Fig. 2, the curves of H = f(Re 0) with cf = consC plotted from the formulas of [6][7][8] also lie close Co the Thompson curves only at values of H and Re e in the middle of the given range of variation.…”

“…The problem of hydrate formation in gas pipelines was first considered in [1][2][3], where the conditions of hydrate formationwere described, and recommendations for the prevention of hydrate formation in gas-plpellne operations were made; these reduce to the need to dry the gas, removecondensed water, and ~nploy pipeline operating conditions that eliminate the possibility of hydrate formation. The problem was then discussed in [4][5][6][7][8][9][10], where attempts were made to determine in advance the sites of possible obstruction of the pipeline by hydrates, and to give a quantitative calculation of the mass of hydrate forming in the course of gas transport. However, these workshave a series of deficiencies.…”

Twenty years after 1989: moving on from transitology

“….sultanistic governance consists only in the extreme development of the ruler's discretion'. 4 The sultanistic polity becomes the personal domain of the 'sultan' and the importance attached to surveillance mechanisms is even more evident than in any other form of non-democratic rule. There is no rule of law, no space for a semi-opposition and no apparent differentiation between hardliners and moderates within the ruling elite.…”