Since they represent fundamental physical properties in turbulence (conservation laws, wall laws, Kolmogorov energy spectrum, . . . ), symmetries are used to analyse common turbulence models. A class of symmetry preserving turbulence models is proposed. This class is refined such that the models respect the second law of thermodynamics. Finally, an example of model belonging to the class is num...

The seminar discusses basic concepts of turbulence modeling in computational fluid dynamics (CFD). There are two mainstreams present in the field of interest. The first one are so called Reynolds averaged Navier-Stokes (RANS) models. RANS models are most widely used nowadays. Therefore theoretical aspects of RANS models are presented in more detail. The second mainstream presents direct numeric...

Recently there has been some progress in modeling the statistical properties of turbulent flows using simple superstatistical models. Here we briefly review the concept of superstatistics in turbulence. In particular, we discuss a superstatistical extension of the Sawford model and compare with experimental data. Turbulence is a spatio-temporal chaotic dynamics generated by the Navier-Stokes eq...

Abstract Zank et al. developed models describing the transport of low-frequency incompressible and nearly turbulence in inhomogeneous flows. The formalism was based on expressing fluctuating variables terms Elsässar then taking “moments” subject to various closure hypotheses. are different according whether plasma beta regime is large, order unity, or small. Here, we show explicitly that three ...

CFD (Computational Fluid Dynamics) simulation is the main research method for assessing the wind environment around building complexes. Recent research showed the importance of turbulence models used in simulation and different turbulence models were developed to improve the precision of CFD simulation results. In this paper, a comparison of different turbulence models in simulating wind enviro...

The aim of the current work is to investigate a series of new subgrid models by employing the Kolmogorov equation of ltered quantities (KEF), which is an exact relation of turbulence in physical space. Di erent formulations of KEF are derived, including the forms in velocity eld (homogeneous isotropic turbulence, inhomogeneous anisotropic turbulence, homogeneous shear turbulence, homogeneous ro...

Shell models of turbulence have been employed as toy models which, in their chaotic states, show statistical properties similar to real fluid turbulence, including Kolmogorov energy spectrum and intermittency. These models are interesting because, at the present stage, it is still quite difficult or almost impossible to study relations between those traditional statistical properties and the st...

The study of compressible homogeneous shear flows has been largely analyzed in literature. Predictions for these flows require an improvement of existing turbulence models. Rapid-distortion-theory (RDT) has largely showed its relevance and its utility to identify compressibility effects which allow us to analyze performances of compressible turbulence models from the existing literature. This p...