Direct numerical simulation (DNS) of turbulent flows is widely recognized to demand fine spatial meshes, small timesteps, and very long run-times to properly resolve the flow field. To overcome these limitations, most DNS is performed on supercomputing machines. With the rapid development of terascale (and, eventually, petascale) computing on thousands of processors, it has become imperative to...

Legacy application software is typically written in a dialect of Fortran, and must be reprogrammed to run on today's microprocessor-based multicomputer architectures. We describe our experiences in modernizing a legacy direct numerical simulation (DNS) code with the KeLP software infrastructure. The resultant code runs on the IBM SP2 with higher numerical resolutions than possible with the lega...

A hybrid direct numerical simulation (DNS) approach is proposed for simulating turbulent collisions of hydrodynamically-interacting particles, under the assumptions that the disturbance flows due to particles are very localized in space and there is a sufficient length-scale separation between the particle size and the Kolmogorov scale of the undisturbed turbulent flow. The approach consists of...

A direct numerical simulation (DNS) code is constructed for solving flow across a three-dimensional deformable bluff body. In the present study, DNS of flow across rigid and compliant cylinders is performed to evaluate the code and the drag reduction effect with a compliant coating. The Strouhal number of shedding of the Karman vortex is calculated and it agrees well with that reported in the l...

We present the large-eddy simulation of the lid-driven cubic cavity flow by the spectral element method (SEM) using three subgrid-scale models. Two spectral filtering techniques suitable for these simulations have been implemented. Numerical results for Reynolds number Re = 12.000 are showing very good agreement with the Direct Numerical Simulation (DNS) results and relatively good agreement wi...

This paper reports a numerical study on the effect of turbulence on the detonation wave properties. The analysis is based on the integration of the chemically reactive Navier– Stokes equations using a Runge–Kutta scheme and a fifth-order WENO spatial discretization. We perform a direct numerical simulation (DNS) of the fluid-mechanics equations in three dimensions to determine the fine-scale ev...

A distributed algorithm for a high-order-accurate finite-difference approach to the direct numerical simulation (DNS) of transition and turbulence in compressible flows is described. This work has two major objectives. The first objective is to demonstrate that parallel and distributed-memory machines can be successfully and efficiently used to solve computationally intensive and input/output i...

A premixed turbulent combustion Direct Numerical Simulation (DNS) database of a swirl burner is analyzed from three angles: estimation of the three-dimensional flame surface from two-dimensional fields; modeling of subgrid source and flux terms entering the balance equation for the reaction progress variable in Large Eddy Simulation (LES); and modeling of the subgrid-scale scalar variance in LE...

A two-phase subgrid combustion model developed earlier has been evaluated for applicability in largeeddy simulations (LES). Direct Numerical Simulations (DNS) of two-phase isotropic turbulence in the presence of passive, momentum-coupled and vaporizing droplets has been extensively studied to form a base-line database. Current DNS results agree with earlier studies and show that the presence of...

The variational multiscale method is applied to the large eddy simulation ~LES! of homogeneous, isotropic flows and compared with the classical Smagorinsky model, the dynamic Smagorinsky model, and direct numerical simulation ~DNS! data. Overall, the multiscale method is in better agreement with the DNS data than both the Smagorinsky model and the dynamic Smagorinsky model. The results are some...