Lift-interference and blockage corrections for two-dimensional subsonic flow in ventilated and closed wind-tunnels.
Abstract:ESDU 76028 gives correction formulae for fully-attached flow on a two-dimensional model spanning the tunnel at mid-height. The tunnel is rectangular-section, has solid side walls and either closed, longitudinally-slotted or perforated roof and floor. The corrections are of two types: lift-interference causing an upwash distribution along the tunnel and blockage. The consequential corrections are given for lift, drag and pitching moment and for the stream quantities: static pressure, density, static temperature and hence Mach number, Reynolds number and kinetic pressure. Their application is explained and care is taken to distinguish in the case of drag corrections between the two cases of either balance measurements or wake traverse.
|Data Item ESDU 76028|
The graphs listed below are available only to subscribers.
|Figure 1||Lift interference parameter δ0|
|Figure 2 Part 1||Lift interference parameter δ1|
|Figure 2 Part 2||Lift interference parameter δ1|
|Figure 3||Solid - blockage factor ratio Ωs|
|Figure 4||Wake - blockage factor ratio Ωw|
|Figure 5a||Solid - blockage gradient factor, 0 ≤ β/P ≤ 2.0|
|Figure 5b||Solid - blockage gradient factor, 2.0 ≤ β/P ≤ 5.0|
|Figure 6||Conditions for zero solid - blockage (Ωs = 0)|