Exact, analytical solutions for practical, fluid flow problems are almost impossible to obtain. Also, because most practical fluid problems are turbulent, and at high Reynolds number, even approximate solutions are limited. Thus, scale model prototyping, and testing are a critical part of any product development program in the aerospace industry. This paper presents state of the art computer procedures which greatly increase the ability to conduct detail model tests more effectively. Computer aided design and data acquisition in conjunction with stereolithography fabrication are shown to allow prototype modifications quickly, and at low costs. Stereolithography techniques are also shown to provide the ability to integrate pressure tap instrumentation into the model fabrication. Computer controlled test facilities, and traverse systems are shown to enhance the gathering, and analysis of large amount of test data.
Sample models, test facilities and data are presented for a jet engine exhaust ejector. Details of the data collection software and analysis procedures are presented. Computer jet traverse data analysis and results are presented for the ejector. Experimental ejector pumping, thrust augmentation and jet mixing results are presented and compared to analytical predictions. The model tests do not include compressibility effects, shock waves, or the non uniform temperature and velocity profiles associated with the actual engine exhaust flow. Furthermore, the model flowfield is at a much lower Reynolds number than the actual flowfield. Even so, computerized data acquisition and model prototype testing of this type can be very helpful in providing insight to the controlling physics, and in generating relative trends needed in the product optimization process.