Computational fluid dynamics simulations and wind tunnel measurements of unsteady wind loads on a scaled model of a very large optical telescope: A comparative study

Unsteady Computational and Experimental Fluid Dynamics Investigations of Aerodynamic Loads of Large Optical Telescopes

“…6. Pressure taps on: (a) the exterior and interior enclosure surfaces, and (b) the primary mirror surface (Mamou et al, 2008) …”

“…Voxel distribution on a plane cutting through the telescope configuration (φ = 30º and ϕ = 0º). The enclosure cross-section is displayed in white (Mamou et al, 2008) …”

“…11d, the opening was totally submerged within the separated flow region, accompanied by low pressure fluctuations inside the enclosure. a) φ = 0º and ϕ = 0º b) φ = 30º and ϕ = 0º c) φ = 30º and ϕ = 30º d) φ = 30º and ϕ = 180º (Mamou et al, 2004a(Mamou et al, , 2008 Snapshot of the off-body streamlines past the enclosure shown in Fig. 12a indicates that the air stream across the opening was intermittently deflected inside and outside the enclosure, owing to the unstable shear layer that formed across the opening.…”

“…12. a) Surface pressure and off-body streamlines colored by the velocity magnitude, b) surface pressure and vorticity iso-surfaces over the floor and the enclosure opening, colored by the static pressure field (φ = 30º and ϕ = 30º) (Mamou et al, 2004a(Mamou et al, , 2008 For a qualitative comparison between CFD predictions and experimental observations, a smoke stream was used in the wind tunnel to visualize the flow behavior around the enclosure structure. Figure 13a displays the smoke stream close to the enclosure opening when it was facing the wind (φ = 30º and θ = 0º), showing a massive flow separation right Fig.…”

“…14. CFD lift and drag force coefficients on the primary mirror assembly (φ = 30º and ϕ = 30º) (Mamou et al, 2008) …”