An improved hybrid Navier-Stokes/full-potential method for computation of unsteady compressible viscous flows |
Posted on:1995-06-09 | Degree:Ph.D | Type:Dissertation |
University:Georgia Institute of Technology | Candidate:Mello, Olympio Achilles de Faria | Full Text:PDF |
GTID:1470390014989762 | Subject:Aerospace engineering |
Abstract/Summary: | |
An improved hybrid method for computing unsteady compressible viscous flows is presented. This method divides the computational domain into two zones. In the outer zone, the unsteady full-potential equation (FPE) is solved. In the inner zone, the Navier-Stokes equations are solved using a diagonal form of an alternating-direction implicit (ADI) approximate factorization procedure. The two zones are tightly coupled so that steady and unsteady flows may be efficiently solved. Characteristic-based viscous/inviscid interface boundary conditions are employed to avoid spurious reflections at that interface. The resulting CPU times are less than 60% of the required for a full-blown Navier-Stokes analysis for steady flow applications and about 60% of the full Navier-Stokes CPU times for unsteady flows in non-vector processing machines. Applications of the method are presented for a rectangular NACA 0012 wing in low subsonic steady flow at moderate and high angles of attack, and for a F-5 wing in steady and unsteady subsonic and transonic flows. Steady surface pressures are in very good agreement with experimental data and are essentially identical to the full Navier-Stokes predictions. Density contours show that shocks cross the viscous/inviscid interface smoothly, so that the accuracy of full Navier-Stokes equations can be retained with a significant savings in computational time. |
Keywords/Search Tags: | Unsteady, Navier-stokes, Method, Flows, Full |
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