Statically stable atmospheric flows are characterized by weak and highly anisotropic turbulence, gravity waves, instabilities, and meandering motions that are not observed in neutral or unstable flows. These features complicate both modeling and measurements in stable boundary layers. Nevertheless, these flows remain of considerable importance for a variety of problems including nighttime flow ...

Hybrid acoustic prediction methods have an important advantage over the current Reynolds averaged Navier-Stokes (RANS) based methods in that they only involve modeling of the relatively universal subscale motion and not the configuration dependent larger scale turbulence. Unfortunately, they are unable to account for the high frequency sound generated by the turbulence in the initial mixing lay...

As part of a larger effort on data-driven turbulence modeling, this paper investigates machine learning models in their capability to reconstruct the functional forms of spatially distributed quantities extracted from high fidelity simulation and experimental data. Such datasets typically involve very high dimensional feature spaces with sparsely populated and noisy data. A new multiscale Gauss...

The present paper deals with the prediction of three-dimensional fluid flow and heat transfer in rib-roughened ducts of square cross-section. Such flows are of direct relevance to the internal cooling system of modern gas turbine blades. The main objective is to assess how a recently developed variant of a cubic non-linear model (proposed by Craft et al. (1999)), that has been shown to produce ...

One of the most promising techniques for the prediction of turbulent flows is Large Eddy Simulation (LES), in which the largest scales of turbulent fluid motion are simulated while the effect of the smaller unresolved scales are modeled. However, one of the major obstacles to the use of LES in technologically important turbulent flows, such as the flow over an airfoil, is the modeling of the ne...

In the present work two turbulence modeling approaches, namely Large Eddy Simulation and Detached Eddy Simulation, are employed to predict the turbulent, swirling flow within an industrial cyclone separator running at Reynolds number 267,000. The results from three LES models, Smagorinsky, dynamic and Yakhot, and the SST-DES model of Strelets have been compared to experimental results for the a...

The presentation will briefly review a Lagrangian model for deforming droplets in turbulence, in which the cumulative deformation of fluid elements at small scales is crucial. In particular, we show how knowledge about the statistical distribution of finite-time Lyapunov exponents (FTLEs) can be used to find a critical Capillary number above which droplets will break up. Probability distributio...

The RANS (Reynolds averaged Navier-Stokes) equations can yield significant error when applied to practical flows involving shock waves. We use the interaction of homogeneous isotropic turbulence with a normal shock to suggest improvements in the k− model applied to shock/turbulence interaction. Mahesh et al. and Lee et al. present direct numerical simulation (DNS) and linear analysis of the flo...

In the last two decades of the 20th century, the world had witnessed the enormous increase in the computational resources. This has brought in the tremendous increase in human knowledge and understanding of complex phenomenon, like turbulence and its modeling among others. The technical development has brought new challenges in engineering design. Whether we limit ourselves to the earthly matte...

The long-term goals of this project are to further the insight into the dynamics of submesoscale flow in the oceanic surface layer. Using the Regional Oceanic Modeling System (ROMS), we aim to understand the impact of submesoscale processes on tracer mixing at small scales and the transfer of energy towards the dissipative scales of non-geostrophic turbulence. An advanced understanding of surfa...