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An unsteady Reynolds-averaged Navier--Stokes solver is applied for the simulation of a synthetic (zero net mass flow) jet created by a single diaphragm piezoelectric actuator in quiescent air. This configuration was designated as case 1 for the Computational Fluid Dynamics Validation 2004 (CFDVAL2004) workshop held at Williamsburg, Virginia, in March 2004. Time-averaged and instantaneous (phase-averaged) data for this case were obtained at NASA Langley Research Center, using multiple measurement techniques. Computational results from two-dimensional simulations with one-equation Spalart--Allmaras and two-equation Menter's turbulence models are presented along with the experimental data. The effect of grid refinement, preconditioning, and time-step variation are also examined.

A new boundary condition is presented for simulating the flow over passively porous surfaces. The model eliminates the need for construction of a grid within an underlying plenum, thereby simplifying the numerical modeling of passively porous flow control systems and reducing computation cost. Two structured-grid flow solvers, TLNS3D and CFL3D, and one unstructured solver, USM3Dns, are used to develop and evaluate the model. Results presented for the three codes on a slender forebody with circumferential porosity and on a wing with leading edge porosity demonstrate good agreement with experimental data and a remarkable ability to predict the aggregate aerodynamic effects of surface porosity with a simple boundary condition.

The artificial boundary condition (ABC) procedure is used in numerical problems involving external flows over finite or configurations of bodies in the subject of fluid dynamics. An ABC is constructed for three-dimensional problems of computational aerodynamics which is a research area that composes but a fraction of the possible range of applications for the different ABC techniques. The novel calculation is discussed.

Four turbulence models were studied for their ability to simulate transonic separated flows. The models, namely, the Baldwin-Lomax, Johnson-King, Baldwin-Barth and Spalart-Allmaras models, were evaluated using the computer codes CFL3D and TLNS3D. Results show that all models are capable of giving fairly accurate estimates despite the effects of numerical truncation errors.

Replacing the scalar artificial dissipation model for artificial viscosity with a matrix-based model improves the accuracy of Navier-Stokes (NS) equations for transonic flows. The matrix model incurs extra costs over those incurred by the scalar model due to the model's increased complexities and spatial offsets. The thin-layer NS equations consider only the viscous diffusion effects which are normal to the test model surface.