Aleksyuk A. I., Osiptsov A. N. Direct numerical simulation of energy separation effect in the near wake behind a circular cylinder // International Journal of Heat and Mass Transfer. — 2018. — Vol. 119. — P. 665–677.
Based on direct numerical simulation of two-dimensional Navier-Stokes equations, the effect of energy separation in unsteady vortex flows is investigated with the reference to the problem of a compressible viscous flow past a thermally insulated circular cylinder. The range of Reynolds (Re⩽1000), Prandtl (0.1⩽Pr⩽10) and Mach (M⩽0.6) numbers considered corresponds mainly to the periodic vortex shedding regime. The energy separation, associated with the vortex shedding process, manifests itself in the appearance of cold and hot (in terms of total temperature) spots in the near wake. The main attention is focused on the comparative analysis of different mechanisms of total-enthalpy variation in a fluid particle moving around the cylinder, such as the action of viscosity, thermal conductivity, and unsteadiness of the flow. It is shown that the time-averaged total-enthalpy stratification in the boundary layer is caused by dissipative mechanisms. In the vortex formation region and in the vortex street, a decrease in the time-averaged total enthalpy is attributable mainly to the streamline oscillations. The known Eckert-Weise effect of low equilibrium temperature at the rearmost stagnation point of the cylinder is associated with the non-uniformities in the temperature and density fields, created by the evolution of recirculation zones near the body surface. For both instantaneous and time-averaged flow patterns, the regions of local increase and decrease in the total enthalpy are distinguished. It turned out that, in the time-averaged flow, the region responsible for the total-enthalpy decrease in the vortex formation zone does not affect the decrease in the total enthalpy in the developed vortex wake, and vice versa.
2018Vavilin V.A., Rytov S.V., Lokshina L.Y. Modelling the specific pathway of CH4 and CO2 formation using carbon isotope fractionation: an example for a boreal mesotrophic fen / Isotopes in Environmental and Health Studies
2018V.A. Vavilin, S.V. Rytov, L.Y. Lokshina. Dynamic isotope equations for 13CH4 and 13CO2 describing methane formation with a focus on the effect of anaerobic respiration in sediments of some tropical lakes / Ecological Modelling, 2018, vol. 386, pages 59-70