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Japan Aerospace Exploration Agency (JAXA) has constructed the JAXA practical pressure-sensitive paint (PSP) measurement system for their large industrial wind tunnels. Its system and application tests were introduced. Contents of the system which included PSP paint, pressure calculation method and apparatus were described. A high accuracy pressure calculation method, a priori/in situ hybrid method, was also introduced and applied to the data processing. For validating this PSP system, an experiment using an ONERA M5 standard model was conducted in a transonic wind tunnel. PSP results represented global quantitative pressure distribution. The PSP data accuracy, 2σ, of the system compared with pressure taps was 1.9 kPa (Cp = 0.06 at M = 0.84). Then, the JAXA practical PSP measurement system was applied to the Japanese regional jet development test. Its results also represented a detailed and global flow structure on the test model. 2σ of PSP data was Cp = 0.06 at cruising condition. It was proved that the present PSP system could be applied to practical tests at a large industrial transonic wind tunnel.

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Pressure-sensitive paint measurement can obtain a much more detailed surface pressure distribution than can be obtained using conventional pressure taps. However, the pressure-sensitive paint is sensitive not only to pressure but also to temperature, and where high accuracy is required, it is essential to compensate for this temperature dependency. This paper discusses data processing methods for pressure-sensitive paint measurement in transonic industrial wind tunnel testing, and proposes three methods to compensate for temperature dependency of the pressure-sensitive paint: an in situ method, an a priori method, and a hybrid of a priori and in situ methods. The pressure distributions from the pressure-sensitive paint data obtained by these proposed methods are compared with pressure tap data measured by conventional pressure transducers, and it is confirmed that the proposed methods are effective in compensating the temperature dependency of pressure-sensitive paint and improve the accuracy of the obtained data. It is also found that the hybrid of a priori and in situ methods is widely applicable to the industrial wind tunnel testing even if the pressure range of the pressure tap data is limited. Nomenclature C p = pressure coefficient C PSP = compensation constant for PSP data C TSP = compensation constant for TSP data f, g = functions of pressure ratio and temperature ratio I = luminescence intensity M = Mach number p = pressure T = temperature x=c = airfoil chordwise coordinate measured from leading edge, normalized by chord = angle of attack = standard deviation Subscripts PT = pressure tap location ref = reference condition in wind tunnel testing refc = reference condition at calibration TM = thermometer location 0 = stagnation condition 1 = freestream conditions

Planar velocity fields of mixing-enhanced compressible planar shear layers are measured via particle image velocimetry (PIV) in order to investigate the mechanism of mixing enhancement by sub-boundary-layer triangular disturbances. The measurements are conducted at convective Mach numbers, $M_{{c}}$, of 0.62 and 0.24 to examine compressibility effects on effectiveness of the mixing enhancement technique. Instantaneous side- and plan-view vector maps of the shear layers are obtained, and turbulence statistical quantities are derived from the instantaneous velocity data. Schlieren and planar laser Mie scattering (PLMS) techniques are also used to measure the shear-layer thickness and growth rate as well as surveying the qualitative flow fields. The velocity fields for several disturbance configurations with different shape, size, or thickness are compared in terms of the shear-layer thickness and growth rate in order to investigate the effects of the configuration variation on the mixing enhancement strategy. Configuration parameters include thickness, the semi-vertex angle of the triangular disturbance, and the streamwise offset of the disturbance from the splitter tip. The measured transverse profile of the mean streamwise velocity shows a characteristic shape with triple inflection points for the effective mixing-enhanced cases at the two different compressibility conditions, while periodic inflection points are observed in the spanwise direction. A pair of stationary counter-rotating streamwise vortices introduced by the subboundary-layer disturbances are also observed, even in the fully developed region of the shear layers. At $M_{{c}}\,{=}\,0.62$, it is found that in successfully enhanced cases, regardless of the disturbance configurations, the present mixing-enhancement strategy has the effect of increasing the turbulence intensity and Reynolds stress, and suppressing the turbulence anisotropy increase with increasing compressibility, i.e. alleviating the compressibility effect which intrinsically reduces pressure–strain-rate redistribution, leading to effective mixing enhancement. Comparison of the results at the two compressibility conditions reveals that the growth rate of the layer is almost constant in the streamwise direction for all cases at $M_{{c}}\,{=}\,0.62$, while for all disturbed cases at $M_{{c}}\,{=}\,0.24$, after an initial layer thickening, growth rate decreases with downstream distance to the value for the undisturbed case, indicating that the present mixing enhancement is less effective at nearly incompressible conditions.