Concept

Wake (physics)

Related publications (127)

Direct numerical simulations of two-phase immiscible wakes

Tammisola et al (2012 J. Fluid Mech. 713 632-58) have observed a counter-intuitive destabilizing effect of the surface tension in planar wakes by means of a global linear analysis. In the present study, we conduct direct numerical simulation (DNS) of wakes ...

Elsevier2014

Increasing Lifetimes and the Growing Saddles of Shear Flow Turbulence

Tobias Schneider, Tobias Klaus Kreilos

In linearly stable shear flows, turbulence spontaneously decays with a characteristic lifetime that varies with Reynolds number. The lifetime sharply increases with Reynolds number so that a possible divergence marking the transition to sustained turbulenc ...

American Physical Society2014

Experimental Investigation of Pressure Fluctuations in a High-Energy Centrifugal Pump Stage at Off-Design Conditions

François Avellan, Mohamed Farhat, Stefan Berten, Philippe Dupont

In centrifugal pumps, the interaction between the rotating impeller blades and the stationary diffuser vanes generates specific pressure fluctuation patterns. At off design operation, high incidence and large local pressure gradients can lead to flow separ ...

Institution of Mechanical Engineers2014

Mitigation measures for fish habitat improvement in Alpine rivers affected by hydropower operations

Anton Schleiss, Martin Peter Bieri, Émilie Person, Armin Julius Peter

In mountainous areas, high-head-storage hydropower plants produce peak load energy. The resulting unsteady water release to rivers, called hydropeaking, alters the natural flow regime. Mitigating the adverse impacts of hydropeaking on aquatic ecosystems ha ...

John Wiley and Sons2014

Volumetric scans of wind turbine wakes performed with three simultaneous wind LiDARs under different atmospheric stability regimes

Fernando Porté Agel, Giacomo Valerio Iungo

Aerodynamic optimization of wind farm layout is a crucial task to reduce wake effects on downstream wind turbines, thus to maximize wind power harvesting. However, downstream evolution and recovery of wind turbine wakes are strongly affected by the charact ...

IOP Publishing Ltd2014

Wind-tunnel experiments of thermally-stratified turbulent boundary layer flow over a wall-mounted 2-D block

Fernando Porté Agel, Wei Zhang, Corey Dean Markfort

Turbulent boundary-layer flows over complex topography have been extensively studied in the atmospheric sciences and wind engineering communities. The upwind turbulence level, the atmospheric thermal stability and the shape of the topography as well as sur ...

2014

Volumetric Lidar Scanning of Wind Turbine Wakes under Convective and Neutral Atmospheric Stability Regimes

Fernando Porté Agel, Giacomo Valerio Iungo

Optimization of a wind farm's layout is a strategic task to reduce wake effects on downstream turbines, thus maximizing wind power harvesting. However, downstream evolution and recovery of each wind turbine wake are strongly affected by the characteristics ...

Amer Meteorological Soc2014

Prediction of the hub vortex instability in a wind turbine wake: stability analysis with eddy-viscosity models calibrated on wind tunnel data

Fernando Porté Agel, François Gallaire, Giacomo Valerio Iungo, Francesco Viola

The evolution and downwind recovery of wind turbine wakes are crucial factors for the evaluation of waketo-wake interactions within a wind farm and, in turn, for the prediction of wind power harvesting. Wind turbine wakes are affected by the design of wind ...

2014

Hysteresis phenomena in hydraulic measurement

Mohamed Farhat, Hongjuan Ran

Hysteresis phenomena demonstrate the lag between the generation and the removal of some physical phenomena. This paper studies the hysteresis phenomena of the head-drop in a scaled model pump turbine using experiment test and CFD methods. These lag is indu ...

Iop Publishing Ltd2013

Large-scale Computation of the Pump-Turbine Rotating Stall

François Avellan, Olivier Pacot, Chisachi Kato

The purpose of this paper is to show the feasibility of a large-scale unsteady flow computation. This computation consists in the simulation of the rotating stall appearing into a pump-turbine operating at part load condition (Q/QBEP=76%) in pumping mode. ...

2013

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