The Crucial Role of Vortical Structure to Jet Swinging Mechanism in a Blind Though Cavity Subjected to a Jet Impingement

0316670 - ÚT 2009 RIV FR eng C - Konferenční příspěvek (zahraniční konf.)
Knob, Martin - Uruba, Václav
The Crucial Role of Vortical Structure to Jet Swinging Mechanism in a Blind Though Cavity Subjected to a Jet Impingement.
[Úloha vírových struktur při proudění paprsku v uzavřené dutině.]
13th International Symposium on Flow Visualization. Besançon: University of Franche Comté, 2008 - (Prenel, J.; Bailly, Y.), s. 1-7. ISBN 0-9533991-8-4.
[International Symposium on Flow Visualization /13./. Nice (FR), 01.07.2008-04.07.2008]
Grant CEP: GA AV ČR IAA2076403; GA ČR GA101/08/1112
Výzkumný záměr: CEZ:AV0Z20760514
Klíčová slova: jet swinging * Coanda effect * shear layer
Kód oboru RIV: BK - Mechanika tekutin

I na blind, retcangular, trough-like cavity subjected to a jet impingement, the jetswitching phenomenon has been known for decades. This is caused by the double-Coanda effect. In the reported research, the TR PIV system was used for the investigation of the vortical structure visualized using the Δ- criterion. On the results obtained, several phenomena are observed. First, on the edges of the jet, the Kelvin-Helmholtz instability forms "large" vortices, which are further entrained by the fluid and grow in size. Second, after the impingement on one of the cavity walls, the flow together with the vortices is bent in the direction towards the cavity opening. At the moment, the vortices start to interact with the just- formed vortices on the edge of the impinging jet-a low pressure zone repsonsible for the jet swingint is created. This phenomenon is investigated for two cavity ratios (2:3 and 3:4), three Reynolds numbers (2300, 11200 and 19600) and four impingement angles (0°, 5°, 10° and 15°).

V práci je experimentálně zkoumán případ proudění paprsku namířeného do uzavřené dutiny. Dochází k přepínání proudového pole. Experimenty byly provedeny pomocí metody TR-PIV. Je sledováno dynamické chování proudového pole, zejména potom vírové struktury vznikající mechanismem Kelvin-Helmholtzovy nestability.
Trvalý link: http://hdl.handle.net/11104/0166518