On non-Newtonian flow past a sphere

Gas hold-up and mass transfer characteristics of packed bubble columns

Non-newtonian nonsimilar boundary layers

This paper is devoted to the theoretical analysis of steady and unsteady boundary layer problems for non-Newtonian power-law fluid flow using a new variational principle ofHamilton's type. The standard method of variational calculus in the form of partial integration is a basic tool for obtaining approximative solutions. The main characteristic of the variational principle developed here is that all basic rules of variational calculus are preserved. The results are found to be in good agreement with those obtained by other authors. Several examples of practical importance, such as steady flow around a flat plate, a wedge and a circular cylinder as well as impulsive motion of a flat plate and a circular cylinder are considered in detail.

A variational principle for the two-dimensional boundary-layer flow of non-newtonian power-law fluids

Die vorliegende Arbeit bringt eine theoretische Untersuchung der laminaren Grenzschichtstromung einer dem Potenzgesetz gehorchenden nichtnewtonschen Flussigkeit hinter einer beliebigen zweidimensionalen Flache. Es wird eine Form der Grenzschichtgleichung hergeleitet, die in der Hinsicht universell ist, das weder die Gleichung noch die Randbedingungen von den besonderen Bedingungen des Problems abhangen. Dies wird dadurch erreicht, das in die Zahl der unabhangigen Variablen eine Schar von Parametern einbezogen wird, die den Einflus der fur ein spezielles Problem charakteristischen Bedingungen ausdrucken. Die universelle Gleichung wird durch eine Parameterapproximation numerisch gelost. Mit Hilfe dieser Losung werden mehrere spezielle Probleme im Detail diskutiert.



This paper presents a theoretical analysis of the laminar boundary layer flow of a non-Newtonian fluid, obeying the power-law model, past an arbitrary two-dimensional surface. The universal form of the boundary layer equation, such that neither the equation nor the boundary conditions depend on the particular conditions of the problem, is derived. This universality is achieved by introducing a set of parameters expressing the influence of external conditions characteristic of a particular problem into a number of independent variables. The universal equation is solved numerically by a parameter approximation. Using this solution several particular problems are analysed in detail.

J.M. Clauss

Papers

On the solution of boundary-layer equations for a non-Newtonian power-law fluid