The identification of laminar-turbulent boundary layer transition on wind tunnel models provides essential data for modem wing design. However, simulating true flight Reynolds numbers with scaled models requires the use of cryogenic wind tunnels. Transition detection in 'war" wind tunnels can be realized using commercially available IR cameras. In parallel, the temperature sensitive paint (TSP) technique is well established as an additional tool. In cryogenic testing IR i m g n g becomes more difficult because of the reduction in radiated energy and the shift to longer wavelengths. Therefore, the TSP technique has become a promising alternative here. However, applying temperature sensitive paint in a large-scale cryogenic wind tunnel like the EuropeanTransonic Wind tunnel (ETW) needs specific modification of existing TSP formulations. Cooperative tests in the ETW therefore were performed by DLR and NAL (Japan). In these measurements, NAL's paint and DLR's mobile PSP/TSP system for data acquisition and evaluati~n'.~.' were used. Some efforts were m d e to adapt the system to specific conditions given at the ETW wind tunnel. So for the first time it was successfully realized to perform a TSP luminescent paint test at cryogenic temperatures in a commercial wind tunnel. Nomenclature Re =Reynolds number Ma =Machnumber p,, T AT 6T a =angle ofattack CL =lift coefficient x*,y*,z* =wing coordinates S = half wing span of model rl =normalized spanwise coordinate (y*/s) x/c =normalized chordwise coordinate = stagnationpressure/temperature in tunnel =total a m u n t of temperature change = temperature difference on wing THE CRYOGENIC WIND TUNNELThe European Transonic Wind tunnel (ETW) sited in Cologne, Germny, i s an industrial cryogenic pressurized facility. It provides the capability for achieving full scale flight Reynolds numbers of transport aircrafi by testing at pressures between 125 and 450 !@a and at temperatures between 110 and 310 K, using nitrogen as the test gas. The tunnel started operation in 1994, and, after a phase of commissioning and evaluation, it is available for productive testing since 19964. Aerodvnarrdc CircuitThe ETW has a closed aerodynamic circuit contained inside an intemally insulated pressure shell. The two stage, fixed blade compressor are driven by a 50 MW synchronous motor. To achieve the desired low tem perahues of the test gas, liquid nitrogen is injected continuously into the tunnel upstream of the compressor. The corresponding gaseous nitrogen exhaust upstream of the stilling chamber is contmlled by valves for the accurate maintenance of tunnel pressure. From the settling chamber equipped with a honeycomb and anti-turbulence screens, the flow enters the test section via a flexible nozzle of contraction ratio 1 : 12 (&I). Figure 1: Aerodynamic circuit of the ETW wind tunnel. LN2: liquid nitrogen, GN2: gaseous nitrogen. 0-7803-8 149-1/03/$17.0002003 IEEE 77The test section has slots in the top and bottom wall for full span model tests and slotted side walls for half model tests. Mach number...

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Detailed experimental and accompanying numerical studies on the development of unsteady wakes past an aircraft under stall conditions are currently prepared by a consortium of research institutions and universities. The experiments will be performed in the ETW cryogenic wind tunnel on the NASA Common Research Model. Besides wake surveys using time-resolved cryo PIV measuring technique, wall interference measurements are planned. The tests scheduled for July 2013 are funded by the European Commission in the 7 th framework program. In this paper results of preparatory CFD studies and wake analyses of the CRM model, the TR-PIV measuring technique and the ETW facility are presented along with the wind tunnel model and the planned test program. Nomenclature CFD = Computational Fluid Dynamics CRM = Comon Research Model b = wing span c = reference chord c l = lift coefficient c p = pressure coefficient DES = Detached Eddy Simulation 2 DPW = Drag Prediction Workshop ESP = Electronically Scanned Pressure ESWI RP = European Strategic Wind Tunnels Improved Research Potential ETW = European Transonic Windtunnel f = frequency HTP = horizontal tail plane k = turbulence kinetic energy L = turbulence length scale L 11 = longitudinal integral length scale LES = Large Eddy Simulation LU-SGS = lower-upper symmetric Gauss-Seidel M ∞ = freestream Mach number NTF = National Transonic Facility (U)RANS = (unsteady) Reynolds-Averaged Navier-Stokes Re = Reynolds number based on the reference chord length RMS = Root Mean Square S = wing reference area St = Strouhal number T t = total temperature TR-PIV = Time-Resolved Particle Image Velocimetry U = velocity U ∞ = freestream velocity x,y,z = Cartesian coordinates y + = wall distance normalized by the viscous length scale α = angle of attack ε = dissipation rate of turbulent kinetic energy η = spanwise position normalized by the wing half span