Detailed hot wire measurements have been successfully collected in the ECL large wind tunnel. They include complete mapping across the nozzle exit plane to provide accurate inlet flow conditions upstream of the CD (controlled diffusion) airfoil. A low turbulence intensity of 0.8% with a spectral content going up to 4000 Hz was found. The approach velocity of 16.72 m/s was used to normalize the experimental measurements. The X-array measurements have provided velocity components at the upper and lower boundaries of the LES computational domain and the airfoil wake at different streamwise locations. The measurements at one station in the wake were repeated with straight wire to assess the experimental repeatability and uncertainty. Quite good agreement was observed. All the mean measurements were then compared to the parallel RANS and LES simulations. These initial results show that even if the local mean pressure distribution is better predicted by the RANS simulations, the computed mean velocity field in the potential core of the jet has only qualitative agreement with those that were measured. The hot-wire measurement suggests a larger deflection of the jet by the presence of the airfoil and a smaller velocity deficit in the airfoil wake. The spectral distributions of the pressure fluctuations at the trailing edge of the airfoil suction side were obtained experimentally and from the LES computations. Good agreement was achieved at low frequencies but the LES spectral values are distinctly smaller than the measured ones starting at f.C/U = 6.8 or 800 Hz, suggesting larger structures in the simulation than in the experiment. The high frequency content seen in the measured pressure spectra might be due to some weak precursor existing in the inlet velocity field shown by the measured spectra at the nozzle exit plane. Further developments will include comparisons of the measured velocity fluctuations in the LES domain with the corresponding simulation results and a full analysis of the boundary layer data at both the leading and trailing edges. This will provide some correlation between the wall pressure statistics and the velocity statistics above some of the Remote Microphones Probes flush mounted on the airfoil.


    Access

    Access via TIB

    Check availability in my library

    Order at Subito €


    Export, share and cite



    Title :

    Hot wire measurements around a cd airfoil in an open-jet anechoic wind tunnel


    Additional title:

    Hitzdrahtanemometrie der Umströmung eines Controlled-Diffusion-Tragflügels in einem offenen echofreien Windkanal


    Contributors:
    Moreau, S. (author) / Neal, D. (author) / Foss, J. (author)


    Publication date :

    2004


    Size :

    5 Seiten, 12 Bilder, 17 Quellen



    Type of media :

    Conference paper


    Type of material :

    Print


    Language :

    English




    The Kevlar-walled anechoic wind tunnel

    Devenport, William J. | Online Contents | 2013


    Fan Acoustic Signatures in an Anechoic Wind Tunnel

    Donald A. Dietrich / Marcus F. Heidmann / John M. Abbott | AIAA | 1977



    Anechoic wind tunnels

    Brouwer, H. H. | TIBKAT | 1997