Transonic flow around airfoils with relaxation and energy supply by homogeneous condensation

Effect of Humidity on Transonic Flow

“…Recent studies on condensation process effects on shock waves were conducted by Schnerr and Dohrmann [1,2], Rusak and Lee [4], and Doerffer et al [6,7]. From their experiments, they observed that significant differences in the normal shock wave structure and shockinduced separation were sensitive to relative humidity variations.…”

“…As the humidity increases, fluctuations in the water vapor increase in the condensation process as well as pressure fluctuations causing the compression or condensation shock waves to form. Schnerr and Dohrmann [1] tested a circular arc model for humidity levels over 0.57. A double-shock system was observed where condensation shock waves appeared ahead of the main shock waves.…”

“…In transonic flow where the shock wave appears, the condensation changes the structure of the entire supersonic flow region around the aerofoil and a double-shock system may appear [1,2]. As a result, moist air around an aerofoil is likely to create complicated flowfields, which are different from dry air, and cause dramatic changes in aerodynamic performance.…”

“…Hence, the disturbances to the boundary layer become smaller and separation may disappear [6,7]. Humidity effects on the shock wave position were examined by Schnerr and Dohrmann [1,2], who used an inviscid fluid flow model for their predictions. A forward shock wave shift was found up until the relative humidity level reached 0.50.…”

“…ONDENSATION is likely to occur on a surface, in transonic flight under humid conditions, having an influence on the aerodynamic performance, such as lift and drag [1][2][3]. Humidityinduced condensation needs to be taken into account in understanding the aerodynamic performance of aircraft.…”