Unsteady viscous flow in the vicinity of a stagnation point

Rott, Nicholas

doi:10.1090/qam/74194

Cited by 176 publications

(74 citation statements)

References 5 publications

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“…This criterion proved to predict the phenomenon correctly and it has been used extensively by both theoreticians and experimentalists for over fifty years. However , Sears [ 2 ] , Moore [3] and Rott (4,5] .~~~~~~ -~~~7…”

Section: Revi Ew Of Literature and Present Extensionsmentioning

confidence: 99%

Unsteady laminar separation: an experimental study

Koromilas

Telionis

1980

J. Fluid Mech.

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The design of most aerodynamic surfaces, as for example the helicopter rotor, is based essentially on quasi-steady theories. However, the dynamics of a rotating blade introduce unexpected fluctuations and overshoots of properties like lift, drag, etc. The phenomenon of unsteady stall is intimately connected with the development of an oscillating boundary layer and separation. Experimental investigation of such flows was undertaken by a method of visualization developed especially for the study of laminar or turbulent boundary layers and separation. The method captures the instantaneous two-dimensional flow field, including regions of separated flow, and provides accurate quantitative information. Laser-doppler anemometer measurements complement the optically obtained data. Results reveal that separation responds with time-lag to external disturbances, in agreement with unsteady stall data. Oscillating outer flows result in displacement of the point of separation and, under certain conditions, the Despard & Miller (1971) criterion was found to hold. Earlier theoretical models of separation are confirmed qualitatively and for the early stages of the transient phenomena. The findings provide physical insight and quantitative data that may help explain the phenomenon of unsteady stall and unsteady separation.

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Section: Revi Ew Of Literature and Present Extensionsmentioning

confidence: 99%

Unsteady laminar separation: an experimental study

Koromilas

Telionis

1980

J. Fluid Mech.

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“…Rott [8] and Glauert [9] studied the stagnation point flow of a Newtonian fluid when the plate performs harmonic oscillations in its own plane. Srivastava [10] investigated the same problem for a non-Newtonian second grade fluid using the Karman-Pohlhausen method [11] to solve the resulting equations.…”

Section: Introductionmentioning

confidence: 99%

Unsteady Stagnation-point Flow of a Second-grade Fluid

Labropulu¹,

Li²

2016

JFFHMT

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“…It was demonstrated for the first time by Prandtl [7,8]. Moore, Rott and Sears (MRS) [9][10][11] presented arguments indicating that the condition (1) is insufficient for unsteady flows. According to MRS, the unsteady separation takes place when the stagnation point and the point of zero stress are located within the flow.…”

Section: Introductionmentioning

confidence: 99%

Vortex patch with wall interaction as new benchmark test

Malecha¹

2011

Open Engineering

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In this paper, a new computational benchmark test for fluid dynamics is presented. The new benchmark is based on the interaction of a single vortex structure (vortex patch) with a wall. It will be shown that it is possible to distinguish two critical or threshold values of the Reynolds number in the considered flow. The increase of the Reynolds number causes the appearance of the vortex bubble in the near-wall region first, and then next, the eruption of the boundary layer phenomenon. Further increase of the Reynolds number causes the flow to be more complex. The eruption phenomenon becomes more intense and also shows its regenerative nature.

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Unsteady viscous flow in the vicinity of a stagnation point

Cited by 176 publications

References 5 publications

Unsteady laminar separation: an experimental study

Unsteady laminar separation: an experimental study

Unsteady Stagnation-point Flow of a Second-grade Fluid

Vortex patch with wall interaction as new benchmark test

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