## K. Hanjalic

350 records found

1

The turbulent penetrative convection into a stable convective boundary layer represents an important phenomenon in environmental engineering and atmospheric science. In the present study, we present a series of numerical simulations performed by two modeling approaches: the hi ...

We report on the application and comparative assessment of two rational turbulence modelling approaches for the computer simulation of air flow and pollutant dispersion in real urban environment: a stand-alone unsteady Reynolds-averaged Navier-Stokes eddy-viscosity model (URAN ...

The paper provides a brief overview of recent computational studies of flow and heat transfer control by rotary oscillations of an infinite circular cylinder at a relatively broad set of imposed frequencies and amplitudes [1, 2]. A study for a previously unreachable high subcr ...

## Reassessment of modeling turbulence via Reynolds averaging

### A review of second-moment transport strategy

This paper examines the evolution of closing the Reynolds-averaged Navier-Stokes equations by approximating the Reynolds stresses via the second-moment transport equations themselves. This strategy first proposed by Rotta is markedly in contrast to the more usual approach of c ...

Large-eddy simulations of a wall-bounded turbulent slot-jet have been performed to analyze the dynamics of quasi-two-dimensional large-scale meandering vortical structures and their interaction with small-scale stochastic turbulence. Despite a wide scale separation, LES indica ...

Seasonal variation of air quality in a city with a large river was investigated by means of numerical simulations of air movement and pollutant dispersion over inversion-capped diurnal cycles using a Reynolds-averaged Navier-Stokes (RANS) approach with algebraic turbulent flux ...

We report on numerical analysis of the effects of inflow conditions on sub-optimal combustion in a coal-dust utility boiler of 230 MW_{e}, believed to be the cause of the observed high-temperature corrosion on fireside membrane walls in the furnace diffuser. To this pu
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We report on a study of the impact of coherent helical vortex structures on the shape of the reaction zone and heat release in swirling methane/air flames in regimes with a vortex breakdown. Three kinds of atmospheric flames are considered, viz., fuel-lean and fuel-rich premix ...

We report on the experimental study of turbulent transport in the near field of swirling jets at Re = 5000 by using simultaneously the stereoscopic particle image velocimetry and planar laser-induced fluorescence methods. The present focus is on the analysis of terms of the me ...

We studied numerically the heat transfer in flow over a rotationally oscillating cylinder at a subcritical Reynolds number (Re=1.4×10^{5}) that is an order of magnitude higher than previously reported in the literature. This paper is a follow-up of the earlier study of
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We studied cavitating flow over the suction side of a symmetric 2D foil - a scaled-down model of high-pressure hydroturbine guide vanes (GV) - in different cavitation regimes at several attack angles. High-speed imaging was used to analyze spatial patterns and time dynamics of ...

## Effects of reburning mechanically-activated micronized coal on reduction of NO_{x}

### Computational study of a real-scale tangentially-fired boiler

The paper presents some results of numerical simulations of the effects of reburning mechanically-activated micronized coal on reduction of NO_{x} and unburnt carbon residual in a tangentially fired boiler of 500 t/h steam production. The conventional RANS approach was
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We report on experimental study of flow and pressure pulsations in draft-tube of a laboratory air model of Francis-99 hydro-turbine operating over a broad range of regimes employing a rapid prototyping of the swirl generators and computerized measurements. In total, 867 operat ...

We report on the experimental investigation of cavitating flow control over a 2D model of guide vanes of a Francis turbine by means of a continuous tangential injection of liquid along the foil surface. The generated wall jet, providing supplementary mass and momentum, issues ...

Reb=5300 based on the bulk velocity U b

Ub and diameter D of the pipe flow.@en

Turbulent jets are known to support large-scale vortical wave packets traveling downstream. We show that a propagating helical wave represents a common form of the "optimal" eigenfunction tracking these structures from the near to the far field of a round jet issuing from a pi ...

We report on a numerical study of the vortex structure modifications and drag reduction in a flow over a rotationally oscillating circular cylinder at a high subcritical Reynolds number, Re=1:4×10^{5}. Considered are eight forcing frequencies f=f_{e}/f_{0
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## Vortex ropes in draft tube of a laboratory Kaplan hydroturbine at low load

### An experimental and LES scrutiny of RANS and DES computational models

We report on the examination of several approaches to simulate computationally the unstable regime of a model Kaplan turbine operating at off-design load. Numerical simulations complemented by laboratory experiments have been performed for a 60:1 scaled-down laboratory turbine ...