We test the functionality of FEniCS on the challenge of computational thermodynamics in the form of the EG2 finite element solver of the Euler equations expressing conservation of mass, momentum and energy. We show that computational solutions satisfy a 2nd Law formulated in terms of kinetic energy, internal (heat) energy, work and shock/turbulent dissipation, without reference to entropy. We s...

The formation of drops at the surface of turbulent liquids, e.g., turbulent primary breakup, was studied experimentally. Pulsed shadowgraphy and holography were used to observe the properties of the liquid surface and the drops formed by turbulent primary breakup. Measured properties included liquid surface velocities, conditions at the onset of ligament and drop formation, ligament and drop si...

The turbulent energy spectra and cospectra of momentum and sensible heat fluxes are examined theoretically and experimentally with increasing flux Richardson number (Rf) in the stable atmospheric surface layer. A cospectral budget model, previously used to explain the bulk relation between the turbulent Prandtl number (Prt) and the gradient Richardson number (Ri) as well as the relation between...

A direct numerical simulation of a turbulent channel flow with a lower curved wall is performed at Reynolds number Reτ ≈ 600. Low-speed streak structures are extracted from the turbulent flow field and base flows formed with conditional streaks averages, superimposing the mean streamwise velocity profile, are used for linear stability analyses. The instability in the presence of a strong pressu...

The α-modeling strategy is followed to derive a new subgrid parameterization of the turbulent stress tensor in large-eddy simulation (LES). The LES-α modeling yields an explicitly filtered subgrid parameterization which contains the filtered nonlinear gradient model as well as a model which represents ‘Leray-regularization’. The LES-α model is compared with similarity and eddy-viscosity models ...

The large range of time and length scales involved in type Ia supernovae (SN Ia) requires the use of flame models. As a prelude to exploring various options for flame models, we consider, in this paper, high-resolution three-dimensional simulations of the small-scale dynamics of nuclear flames in the supernova environment in which the details of the flame structure are fully resolved. The range...

Large-eddy simulations described here have included the effect of canopy drag through the depth of a plant canopy. Specifically, we have considered the simulation of flow through a forest. Drag forces enter the simulation with the inclusion of form and viscous drag forces in the momentum equation. In addition, we have carried a variable to represent the kinetic energy (KE) associated with the t...