Flow-visualization studies on three-dimensional bluff bodies.
نویسندگان
چکیده
منابع مشابه
Three Dimensional Flow Development in the Wake of Elongated Bluff Bodies
The results from Floquet stability analysis of the flow around nominally two-dimensional long plates with elliptical leading edges and blunt trailing edges are presented, elucidating the early stages of wake transition to turbulent flow. Three modes of instability are found: Mode A, Mode B and a period doubling mode. The first two of these also occur in wake transition for circular cylinders an...
متن کاملReflectional symmetry breaking of the separated flow over three-dimensional bluff bodies.
Experimental observation of a permanent reflectional symmetry breaking (RSB) is reported for a laminar three-dimensional wake. Based on flow visualizations, a first bifurcation from the trivial steady symmetric state to a steady RSB state is characterized at Re=340. The RSB state becomes unsteady after a second bifurcation at Re=410. It is found that this RSB regime is persistent at large Reyno...
متن کاملFlow Visualization Studies on Trapezoidal Bluff Body for Vortex Flowmeter Appication
In the present study, turbulent flow visualization is carried out to understand the vortex formation mechanism behind a trapezoidal bluff body, for vortex flowmeter application. The dye used for flow v isualization is shearthickening and h igh extension viscosity fluid, which can sustain turbulent separated flows. W ith the quantitative assessment of the images, the vortex frequency is computed...
متن کاملFlow Control around Bluff Bodies by Attached Permeable Plates
The aim of present study is to control the unsteady flow structure downstream of a circular cylinder by use of attached permeable plates. Particle image velocimetry (PIV) technique and dye visualization experiments were performed in deep water and the flow characteristics were evaluated by means of time-averaged streamlines, Reynolds Shear Stress and Turbulent Kinetic Energy concentrations. The...
متن کاملOn three-dimensional quasiperiodic Floquet instabilities of two-dimensional bluff body wakes
Previous studies dealing with Floquet secondary stability analysis of the wakes of circular and square cross-section cylinders have shown that there are two synchronous instability modes, with long ~mode A! and short ~mode B! spanwise wavelengths. At intermediate wavelengths another mode arises, which reaches criticality at Reynolds numbers higher than modes A or B. Here we concentrate on these...
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ژورنال
عنوان ژورنال: JOURNAL OF THE FLOW VISUALIZATION SOCIETY OF JAPAN
سال: 1984
ISSN: 1884-0361,0287-3605
DOI: 10.3154/jvs1981.4.124