Numerical Simulation of Flow Over a Submerged Hemispherical Flat-Window Turret

Highdelity implicit large eddy simulation (HFILES) have been performed for ow over a 3-D at-window hemispherical turret mounted on a surface for both the baseline ow and for the case of steady suction through a slot at the edge of the aperture to control separation. The on-coming boundary layer is 45% the height of the turret. The diameter of the at-window aperture is 48% of the turret diameter and is oriented symmetric to the oncoming ow at an elevation angle of 138. The ow conditions were M = 0:10 and ReH = 50; 000. This geometry is modeled after an experiment performed at the University of Florida. The HFILES computations were obtained using a well-validated high-order NavierStokes ow solver employing a 6-order compact spatial discretization in conjunction with a 8-order low-pass spatial lter. The simulations were performed on both 57M and 127M point mesh systems using a massively parallel computing platform and a high-order overset grid methodology. Qualitative comparisons are made with the experiment and previous simulations of a at-window hemispherical turret on a cylindrical base. Overall, solutions compared favorably to experimental time mean solutions and oilow visualization. This study demonstrates that steady suction at the edge of the aperture can be successfully employed to signi cantly reducing ow separation at large look angles in the wake of the turret which is critical in reducing aero-optical aberrations.

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