Three-dimensional instability of anticyclonic swirling flow in rotating fluid: Laboratory experiments and related theoretical predictions

1998 ◽  
Vol 10 (12) ◽  
pp. 3194-3202 ◽  
Author(s):  
Ya. D. Afanasyev ◽  
W. R. Peltier
Keyword(s):  
Laboratory Experiments ◽  
Swirling Flow ◽  
Three Dimensional ◽  
Rotating Fluid ◽  
Theoretical Predictions ◽  
Dimensional Instability

The entrainment envelope of dye-core vortices at submerged hydraulic intakes

2002 ◽  
Vol 29 (3) ◽  
pp. 400-408 ◽  
Author(s):  
E C Carriveau ◽  
R E Baddour ◽  
G A Kopp
Keyword(s):  
Water Surface ◽  
Laboratory Experiments ◽  
Swirling Flow ◽  
Three Dimensional ◽  
Swirling Flows ◽  
Surface Phenomenon ◽  
Acoustic Doppler Velocimeter ◽  
Velocity Measurements ◽  
Frazil Ice ◽  
Hydraulic Intake

Each winter in Canada, operational difficulties are encountered at various water works resulting from intake blockages caused by frazil ice entrainment. In a lake setting, frazil is a surface phenomenon, the strong downward current produced by a swirling flow, with an intake vortex present, provides a mechanism by which frazil is transported from the water surface to the submerged intake below. Laboratory experiments were conducted to study the entrainment envelope associated with swirling and non-swirling flows into submerged water intakes. Three-dimensional velocity measurements were made with an acoustic Doppler velocimeter. The results clearly show that the entrainment envelope for swirling flow is several times larger than that for non-swirling flow. This paper details, for a given set of conditions, the differences in the non-swirling and swirling flow entrainment envelopes and emphasizes the potential difficulties with frazil ice that vortices can cause at intakes.Key words: vortex, dye-core vortex, submerged hydraulic intake, entrainment envelope, three-dimensional velocity measurements, acoustic Doppler velocimeter.

Tilt-induced instability of a stratified vortex

2008 ◽  
Vol 596 ◽  
pp. 1-20 ◽  
Author(s):  
NICOLAS BOULANGER ◽  
PATRICE MEUNIER ◽  
STÉPHANE LE DIZÈS
Keyword(s):  
Froude Number ◽  
Three Dimensional ◽  
Axial Flow ◽  
Companion Paper ◽  
Shear Instability ◽  
Critical Layer ◽  
Theoretical Predictions ◽  
Layer Region ◽  
Sudden Decrease ◽  
Dimensional Instability

This experimental and theoretical study considers the dynamics and the instability of a Lamb–Oseen vortex in a stably stratified fluid. In a companion paper, it was shown that tilting the vortex axis with respect to the direction of stratification induces the formation of a rim of strong axial flow near a critical radius when the Froude number of the vortex is larger than one.Here, we demonstrate that this tilt-induced flow is responsible for a three-dimensional instability. We show that the instability results from a shear instability of the basic axial flow in the critical-layer region. The theoretical predictions for the wavelength and the growth rate obtained by a local stability analysis of the theoretical critical-layer profile are compared to experimental measurements and a good agreement is observed. The late stages of the instability are also analysed experimentally. In particular, we show that the tilt-induced instability does not lead to the destruction of the vortex, but to a sudden decrease of its Froude number, through the turbulent diffusion of its core size, when the initial Froude number is close to 1. A movie is available with the online version of the paper.

Evolution of isolated vortices in a rotating fluid of finite depth

1999 ◽  
Vol 381 ◽  
pp. 239-269 ◽  
Author(s):  
P. ORLANDI ◽  
G. F. CARNEVALE
Keyword(s):  
Laboratory Experiments ◽  
Three Dimensional ◽  
Finite Depth ◽  
Ekman Layer ◽  
Rotating Flow ◽  
Two Dimensional ◽  
Barotropic Instability ◽  
Rotating Fluid ◽  
Vortex States ◽  
Centrifugal Instability

Laboratory experiments have shown that monopolar isolated vortices in a rotating flow undergo instabilities that result in the formation of multipolar vortex states such as dipoles and tripoles. In some cases the instability is entirely two-dimensional, with the vortices taking the form of vortex columns aligned along the direction of the ambient rotation at all times. In other cases, the vortex first passes through a highly turbulent three-dimensional state before eventually reorganizing into vortex columns. Through a series of three-dimensional numerical simulations, the roles that centrifugal instability, barotropic instability, and the bottom Ekman boundary layer play in these instabilities are investigated. Evidence is presented that the centrifugal instability can trigger the barotropic instabilities by the enhancement of vorticity gradients. It is shown that the bottom Ekman layer is not essential to these instabilities but can strongly modify their evolution.

Asymmetric Swirling Flows in Turbomachine Annuli

1978 ◽  
Vol 100 (4) ◽  
pp. 618-629 ◽  
Author(s):  
E. M. Greitzer ◽  
T. Strand
Keyword(s):  
Experimental Investigation ◽  
Swirling Flow ◽  
Three Dimensional ◽  
Swirling Flows ◽  
Experimental Measurements ◽  
Strongly Coupled ◽  
Flow Disturbances ◽  
Different Types ◽  
Theoretical Predictions ◽  
Good Agreement

An analytical and experimental investigation of asymmetric annular swirling flows is presented. It is shown that, in contrast to the situation in nonswirling flow, the different types of flow disturbances (pressure and vorticity) are not separable in a swirling flow but are strongly coupled. The flows that occur due to this coupling are inherently three-dimensional and exhibit new features not seen in the nonswirling case. The theoretical predictions are in good agreement with experimental measurements carried out in an annular swirl rig.

THREE-DIMENSIONAL LAMINAR SWIRLING FLOW IN A PIPE

2019 ◽  
Author(s):  
Rodrigo Vidal Cabral ◽  
Andre Damiani Rocha
Keyword(s):  
Swirling Flow ◽  
Three Dimensional

scholarly journals Liquid water infiltration into a layered snowpack: evaluation of a 3-D water transport model with laboratory experiments

2017 ◽  
Vol 21 (11) ◽  
pp. 5503-5515 ◽  
Author(s):  
Hiroyuki Hirashima ◽  
Francesco Avanzi ◽  
Satoru Yamaguchi
Keyword(s):  
Liquid Water ◽  
Laboratory Experiments ◽  
Preferential Flow ◽  
Transport Model ◽  
Three Dimensional ◽  
Water Infiltration ◽  
Flow Paths ◽  
Preferential Flow Paths ◽  
Capillary Barriers ◽  
Wet Snow

Abstract. The heterogeneous movement of liquid water through the snowpack during precipitation and snowmelt leads to complex liquid water distributions that are important for avalanche and runoff forecasting. We reproduced the formation of capillary barriers and the development of preferential flow through snow using a three-dimensional water transport model, which was then validated using laboratory experiments of liquid water infiltration into layered, initially dry snow. Three-dimensional simulations assumed the same column shape and size, grain size, snow density, and water input rate as the laboratory experiments. Model evaluation focused on the timing of water movement, thickness of the upper layer affected by ponding, water content profiles and wet snow fraction. Simulation results showed that the model reconstructs relevant features of capillary barriers, including ponding in the upper layer, preferential infiltration far from the interface, and the timing of liquid water arrival at the snow base. In contrast, the area of preferential flow paths was usually underestimated and consequently the averaged water content in areas characterized by preferential flow paths was also underestimated. Improving the representation of preferential infiltration into initially dry snow is necessary to reproduce the transition from a dry-snow-dominant condition to a wet-snow-dominant one, especially in long-period simulations.

Three-dimensional instability of an elliptic Kirchhoff vortex

1988 ◽  
Vol 23 (3) ◽  
pp. 356-360 ◽  
Author(s):  
V. A. Vladimirov ◽  
K. I. Il'in
Keyword(s):  
Three Dimensional ◽  
Dimensional Instability
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