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In this work, the flow velocity distribution was determined by measurements of visualized flow, obtained with a one-fourth scale three-dimensional model, and by numerical analysis. The measurements of interior flow were obtained using a method which combined the particle-tracking technique, a basic method conventionally employed for flow visualization, with a pulsed-laser-light-sheet technique. Flow images taken with a video camera were then processed by means of an image processing system. Flow velocity distributions were obtained for two different discharge modes - a dashboard-vent mode in which air was discharged from four vents provided along the top of the dashboard, and a bi-level mode in which vents at the foot position were added to those of the first mode. Three-dimensional numerical analyses using a direct-simulation method were conducted to calculate the interior flow, and a comparison was made with the measured results obtained in the visualization experiment.

Flow velocity distributions in the passenger compartment were measured from visualized images of particle flow paths obtained with a full-scale model. The flow paths were visualized using an approach that combined a particle tracing method with a pulse-laser light technique. Air was used as the fluid medium with the full-scale passenger compartment model and water was used as the fluid medium with a one-fourth scale model. A comparison of the results obtained with the two models confirmed that there was good agreement between the flow velocity distributions. Using the full-scale model, measurements were also made of the flow velocity distributions when two dummies were placed in the front-seats.

Numerical simulation of two-dimensional and three-dimensional air flow in automobile passenger compartments is described. The flow can be expressed by means of an incompressible Navier-Stokes equation for a narrow temperature range. The results were represented visually using animation and a color graphics system. The two-dimensional simulation showed that heat ansfer takes place chiefly by convection in vortices, and that the effects of heat transfer are minimal. In the three-dimensional analysis, shading was used to show the shape inside the compartment, and instantaneous stream lines and temperature distribution were depicted. The three-dimensional stream lines swirl upward at the front seat, and do not reach the back seat. The results gained from this study show that present theoretical flow analysis methods are close to being perfected. Further advances will require additional refinement of supercomputers and graphic engineering workstations.