SAE J 2071:1994 PDF Download

The SAE J 2071:1994 standard addresses the impact of various factors on wind tunnel testing of vehicles. These factors include flow quality, determination of the reference dynamic pressure, wind tunnel floor boundary layer, test section geometry, shape of the vehicle, blockage ratio, wheel rotation, and internal flow in the model.

The standard aims to document the knowledge of model interference on wind tunnel test results for automotive open jet wind tunnels. It includes design data of open throat wind tunnels, a summary of published and unpublished test data, and documentation and theoretical explanations of different blockage correction procedures for automotive tests.

The standard also provides a critical evaluation of blockage correction procedures in relation to other influences, such as test section geometry, position of the car, and floor boundary layer. It recommends a calibration procedure to determine the effect of blockage and other influences in each individual wind tunnel.

However, the standard states that a well-proven correction procedure based solely on blockage theory could not be established at the time of publication. This is because factors other than blockage, such as test section geometry, have a significant influence on wind tunnel testing results. Since these influential parameters vary from wind tunnel to wind tunnel, a universally applicable adjustment procedure is not currently available.