A new technique has been developed for the presentation of data obtained in three-dimensional finite difference calculations. The technique consists of an especially simple and efficient method for the generation of perspective pictures with hidden lines removed. These pictures may contain distributions of marker particles, velocity vectors, contour lines, streak-lines, etc., in relation to an array of prismatically shaped obstacles. With this technique the gross features of many complex three-dimensional problems can be readily understood.

A computing technique for low-speed fluid dynamics has been developed for the calculation of three-dimensional flows in the vicinity of one or more block-type structures. The full time-dependent Navier-Stokes equations are solved with a finite-difference scheme based on the Marker-and-Cell method. Effects of thermal buoyancy are included in a Boussinesq approximation. Marker particles that convect with the flow can be used to generate streaklines for flow visualization, or they can diffuse while convecting to represent the dispersion by turbulence of particulate matter. The vast amount of data resulting from these calculations has been rendered more intelligible by perspective-view and stereo-view plots of selected velocity and marker-particle distributions.

A new method is presented for the numerical solution of the transient flow of viscous incompressible fluids having free surfaces. The method is based on Lagrangian coordinates in contrast to other methods, which use the Eulerian representation. Lagrangian coordinates permit the accurate treatment of fluid interfaces and free surfaces, and make it a simple matter to include the effects of surface tension. Several examples illustrate the properties of this new technique.