In the current study, model expressions for fifth-order velocity moments obtained from truncated Gram-Charlier series expansions a turbulent flow field probability density function are validated using data direct numerical simulation (DNS) of planar in strained channel. Simplicity expressions, lack unknown coefficients, and their applicability to non-Gaussian flows make this approach attractive...

Nodal methods are the backbone of the production codes for neutron-diffusion and transport equations. Despite their high accuracy, use of these methods for simulation of fluid flow is relatively new. Recently, a modified nodal integral method (MNIM) has been developed for simulation of laminar flows. In view of its high accuracy and efficiency, extension of this method for the simulation of tur...

This study presents a method to perform direct numerical simulation (DNS), in the sense of turbulence, two-phase flows with interfaces. It is based on compressible diffuse interface model introduced by second gradient theory. assumes continuous variation thermodynamic variables and add their description dependency density gradient. The widths as predicted fall way below typical relevant turbule...

We investigate and model pressure effects on the turbulent burning velocity over a range of pressures turbulence intensities with direct numerical simulation (DNS) statistically planar premixed flames for lean hydrogen/air mixture. DNS results indicate that stretch factor has an impact flame surface area at elevated pressures. In particular, enhanced high increases ratio laminar velocities, dim...

There are different methods for setting the inlet boundary condition (IBC) in large eddy simulation (LES). However, applied same result results. In this study, influence of IBC LES with Lund method, divergence-free synthetic eddies method (DFSEM), and digital filter (DFM) on layer over a flat plate was investigated. For DFM DFSEM, input parameters such as turbulent length scales constant values...

With the long-term objective of Critical Heat Flux (CHF) prediction, a Direct Numerical Simulation (DNS) framework for simulation of subcooled and saturated nucleate pool boiling is developed. One case of saturated, and three cases of subcooled boiling at different subcooling levels are simulated. Grid refinement study is also reported. Both boiling and condensation phenomena can be computed si...

A technique for measuring the mean impulse response function of stationary homogeneous isotropic turbulence is proposed. Such a measurement is carried out here on the basis of direct numerical simulation (DNS). A zero-mean white-noise volume forcing is used to probe the turbulent flow, and the response function is obtained by accumulating the space-time correlation between the white forcing and...

Comparisons between direct numerical simulation (DNS) of detonation and detonation shock dynamics (DSD) is made. The theory of DSD defines the motion of the detonation shock in terms of intrinsic geometry of the shock surface, in particular for condensed phase explosives the shock normal velocity, Dn, the normal acceleration, Ḋn, and the total curvature, κ. In particular, the properties of thre...

Dynamic models for large eddy simulation of the G-equation of turbulent premixed combustion are proposed and tested in forced homogeneous isotropic turbulence. The basic idea is to represent the ‘‘filtered propagation term’’ as ‘‘propagation of the filtered front at higher speed,’’ where the enhanced filtered-front speed is modeled. The validity of the linear relation between the turbulent flam...

Large-eddy simulation (LES) mainly consists of a “projection”: an effective “truncation” to much fewer modes than what is required to perform a direct numerical simulation (DNS). This can be done in different ways: using a reduced set of discrete field values (formally equivalent to sampling, on the coarse grid, of the continuous DNS field), or using a reduced set of continuous functions, etc. ...