How to Accurately Measure Low Sonic Boom or Model Surface Pressure in Supersonic Wind Tunnels

R 3/4 scaling. Methodology being developed for general acoustic (linear) ray spreading was applied to sonic boom and (non- linear: required for large initial sonic boom overpressure) aging was applied separately. Acoustic conical ray spreading meant a slower amplitude decay that varies with R ½ scaling; therefore, the rest of the observed amplitude decay was due to non-linear aging or stretching of the signature. Measurement distance in a wind tunnel is affected by both aging and acoustic propagation concerns.