Manoeuvring underwater vehicles experience complex three dimensional flow. Features include stagnation and boundary layer separation along a convex surface. The resulting free vortex sheet rolls up to form a pair of streamwise body vortices. The track and strength of the body vortex pair results in a nonlinear increase in lift with as body incidence increases. Consequently, accurate capture of ...

A method for generating three-dimensional, time-dependent turbulent inflow data for simulations of complex spatially developing boundary layers is described. The approach is to extract instantaneous planes of velocity data from an auxiliary simulation of a zero pressure gradient boundary layer. The auxiliary simulation is also spatially developing, but generates its own inflow conditions throug...

The unsteady discrete adjoint equations are utilized to construct objective function gradients for use in geometry optimization in large scale three-dimensional unsteady ow problems. An existing massively parallel unstructured Reynolds-averaged Navier-Stokes equations solver forms the basis for the framework used to solve both the primal and dual (adjoint) problems. The framework is also capabl...

A spectral element—Fourier method (SEM) for Direct Numerical Simulation (DNS) of the turbulent flow of non-Newtonian fluids is described and the particular requirements for non-Newtonian rheology are discussed. The method is implemented in parallel using the MPI message passing kernel, and execution times scale somewhat less than linearly with the number of CPUs, however this is more than compe...

The intent of shielding functions in delayed detached-eddy simulation methods (DDES) is to preserve the wall boundary layers as Reynolds-averaged Navier–Strokes (RANS) mode, avoiding possible modeled stress depletion (MSD) or even unphysical separation due to grid refinement. An entropy function f s is introduced to construct a DDES formulation for the k-ω shear stress transport (SST) model, wh...

The nonstationary separated incompressible flows around Darrieus and Savonius rotors of vertical-axis wind turbines were investigated through computational simulation using the Reynolds averaged Navier–Stokes equations Spalart–Allmaras turbulence model. implicit finite-volume algorithm, basis which was artificial compressibility method, chosen to obtain numerical solution. series physical exper...

Ground effect phenomenon is found when the lift-device such as wing, placed near ground. This influences aerodynamics characteristic whereby its appearance important to be investigated. work aims study influence of ground towards characteristion on NACA4415 airfoil by varying airfoil’s angle attack (AoA) well height proximity. Numerical approach conducted Fluent was carried out while steady ass...

This paper highlights the results and comparison of flow topology investigation above unmanned combat aerial vehicle (UCAV) configuration, namely, multidisciplinary design configuration (MULDICON), with modified leading-edge profile at apex region from a sharp to blunt reduce complexity structure wing. It was found visualization that low angle attack, for instance, 10°, onset separation took pl...

Abstract The vortex-dominated flow around the triple-delta wing ADS-NA2-W1 aircraft is investigated in order to achieve a better understanding of physics phenomena that occur over particularly at transonic speed condition. Both URANS and scale-resolving DDES have been employed explore range suitability current CFD methods. Spalart–Allmaras One-Equation Model with corrections for negative turbul...