This article reviews some recent applications of the transient-Reynoldsaveraged Navier-Stokes (T-RANS) approach in simulating complex turbulent flows dominated by externally imposed body forces, primarily by thermal buoyancy and the Lorentz force. The T-RANS aims at numerical resolving unsteady (semi-) deterministic vortical structures in flows with sufficiently strong internal forcing. With a well-tested RANS model to account for the unresolved 'subscale' motion, the T-RANS is considered as a

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... ool for solving large-scale high Rayleigh and Reynolds numbers, which are inaccessible to the conventional large-eddy simulation (LES) or any other numerical simulation approach. First, a brief outline of the T-RANS rationale is presented and its potential illustrated in the simulation of Rayleigh-Bérnard convection in an infinite domain for over a ten-decade range of Rayleigh numbers (10 6 -2 × 10 16 ). The accurate prediction of heat transfer over a wide range of Rayleigh numbers provided sufficient credibility in the approach and its application to a variety of real-life flows dominated by body forces. This is illustrated by three examples of complex environmental and multi-physics phenomena: dynamics of a fuel-oil cooling inside a sunken tanker wreck, diurnal variations of air-movement and pollutant spreading over a mesoscale mountain city in a valley capped by a thermal inversion layer, and finally in the generation and self-sustenance of a magnetic field by a highly turbulent helical sodium movement. The simulated results agree well with the experimental data where available.