Sergey L. Chernyshev , Alexander I. Ivanov , Andrey Ph. Kiselev, Vladimir Ye. Mosharov , Tatiana M. Pritulo , Dmitriy S. Sboev , Leinid L. Teperin , and Vladimir G. Yudin
DOI Number XXX-YYY-ZZZ
Conference Number HiSST 2018_1710851
The possibilities of the experimental-numerical technique improving of sonic boom estimation are analyzed. This technique is based on the gasdynamic flow characteristics measuring at near aircraft model flow-field in the wind tunnels (WT). First it is measured the disturbed pressure at the model near-field at the WT test section. Then obtained data are recalculated for the large distances by using the quasi-linear theory. For pressure definition at model near-field it was suggested the method that used the luminescent pressure transducers (pressure-sensitive paints, PSP). The PSP technique is based on the phenomenon of fluorescence quench of the organic luminophore by using the air oxygen. To realize this method the surface under investigation is covered with the special paint like thin polymer layer. This thin layer is permeable for the oxygen and contains the luminophore molecules. The luminophore becomes excited by the light of corresponding wave length and the fluorescence intensity or the life time of excited molecules were measured. The fluorescence intensity and molecule life time are inversely proportional to the pressure. It appears that at the distances from the body about 5-10 aircraft length the flow becomes significantly simplified. Three dimensional flow near the aircraft is transformed into a flow over the equivalent body of revolution. So the initial data for sonic boom calculation should be obtained using the Yu.L. Zhilin’s theorem. According to it the derivative of cross-section area of equivalent body of revolution can be defined by the integral of the disturbed pressure coefficient at the aircraft near-field along the certain surface. This surface should be placed at the small distance about 0.1–0.5 aircraft length from it. The results of pressure distribution measuring at aircraft model near-field performed at TsAGI wind tunnels are presented. The measured pressure distributions as a rule possess the irregular perturbations caused by the experiment peculiarities. The last ones can distort the results for Zhilin’s integral obtaining. It was supposed the special procedure of handling of pressure measuring results obtained by using the PSP. This procedure based on wavelet analysis methods allows to decrease the random noise influence and to rise the accuracy of pressure field integration in order to define the equivalent body of revolution form. The possibility of construction of measuring system based on the PSP method for the investigation of aircraft model near-field at the large industrial supersonic TsAGI wind tunnel T-109 was considered.