Outline of the Wind-Tunnel Configuration

  1. Blower
    The 400kW blower is located in the second basement floor and provides the pressure head that drives the air stream. The maximum air-volume flux is 820 000 m³/h at 750 rpm.

  2. Turning Section
    A total of four turning sections (i.e. 2 x 2 consecutive 90° bends) equipped with 10, 11, 15 and 19 guide vanes - depending on the width of the cross section - are implemented. The chord of the guide vanes is assigned to 850mm, the chord to gap ratio is 0.25 - 0.35.

  3. Settling Chamber
    The settling chamber host three sections to trim the flow field thermodynamically and kinematically
    1. Cooler
      The temperature of the air stream increases during the operation of the tunnel due to viscous (frictional) effects. The latter alters both, the density and the viscosity of the fluid. Thus a cooling section (by means of a heat exchanger) is required to keep the temperature and properties of the fluid constant during the operation of the tunnel.
    2. Honey-Comb
      In order to achieve a uni-directional flow field, a honey-comb grid, featuring 150mm long cells with approximately 10mm edge length are implemented.
    3. Scrrens
      Three small-meshed screens are utilised to achieve a homogeneous flow field.
  4. Nozzle
    The air stream is accelerated in the nozzle. The contraction of the wide (3m x 2m exit section) nozzle is 4.125. The small (2m x 2m) nozzel features a contraction of 6.19.

    In order to suppress coherent vortical structures, the nozzle is equipped with Seiferth flaps, which transfer energy to smaller scale broad-band structures.

  5. Test Section
    The test section is 5.5 m long and hosts a centred, 360° turning table which is connected to an external SCHENCK subfloor 6-component ballance. The open test section features manual and optical access from the top side and the two lateral sides. It can optionally be closed. Moreover the test section can be swapped behind the collector section.

  6. 6-Component Balance
    The balance can measure forces up to 200N (400N) and moments up to 200N. The balance is mounted on a rail-bounded table which can be moved in axial direction.

  7. Collector / Diffusor
    The air stream is collected and remaining pressure is recovered in the diffusor section, which moderately opens up the cross sectional area in downstream direction.

  8. Doors to Swap from Open-Section to Closed-Section Mode
    In order to allow for flow visualisation based on smoke etc., doors can be opened which blend form closed section mode to open section mode. In the open section mode, external air is supplied to the blower and the air stream is directed to the outside aft of the collector.