实验流体力学
實驗流體力學
실험류체역학
JOURNAL OF EXPERIMENTS IN FLUID MECHANICS
2014年
6期
56-60
,共5页
何惠琴%翟志刚%司廷%罗喜胜
何惠琴%翟誌剛%司廷%囉喜勝
하혜금%적지강%사정%라희성
无膜气柱%Richtmyer-Meshkov不稳定性%反射激波%Atwood数%连续片光
無膜氣柱%Richtmyer-Meshkov不穩定性%反射激波%Atwood數%連續片光
무막기주%Richtmyer-Meshkov불은정성%반사격파%Atwood수%련속편광
membrane-less gas cylinder%Richtmyer-Meshkov instability%reshock%Atwood number%continuous laser sheet
在水平方形激波管中对两种无膜重气柱界面(分别是SF6和氩气)在反射激波作用下的不稳定性发展进行了实验研究。气柱界面采用射流技术形成,实验采用连续激光片光源照射流场,乙二醇作为示踪粒子,并用高速摄像机对流场进行拍摄,获得了入射激波以及反射激波共同作用下,两种不同气柱界面的演化过程。实验结果表明,两种气柱的Atwood数不同,界面演化速率不同,反射激波到达前后的界面形态不同。SF6气柱在入射激波作用下会产生两个比较明显的反向的涡环结构,而氩气柱界面上由于产生的涡量较少,涡环结构并不明显。在反射激波作用下,SF6气柱界面会出现明显的次级涡对,而且次级涡对的旋转方向与初始涡环结构的旋转方向相反。对于氩气柱而言,在反射激波作用下虽然也产生了与初始涡环方向相反的次级涡对,但次级涡对始终未充分发展。这是因为反射激波作用时氩气柱界面的Atwood数较小导致氩气柱界面上产生的反向涡量较少。实验结果充分表明了气体Atwood数对界面不稳定性的发展起到了较大的影响。
在水平方形激波管中對兩種無膜重氣柱界麵(分彆是SF6和氬氣)在反射激波作用下的不穩定性髮展進行瞭實驗研究。氣柱界麵採用射流技術形成,實驗採用連續激光片光源照射流場,乙二醇作為示蹤粒子,併用高速攝像機對流場進行拍攝,穫得瞭入射激波以及反射激波共同作用下,兩種不同氣柱界麵的縯化過程。實驗結果錶明,兩種氣柱的Atwood數不同,界麵縯化速率不同,反射激波到達前後的界麵形態不同。SF6氣柱在入射激波作用下會產生兩箇比較明顯的反嚮的渦環結構,而氬氣柱界麵上由于產生的渦量較少,渦環結構併不明顯。在反射激波作用下,SF6氣柱界麵會齣現明顯的次級渦對,而且次級渦對的鏇轉方嚮與初始渦環結構的鏇轉方嚮相反。對于氬氣柱而言,在反射激波作用下雖然也產生瞭與初始渦環方嚮相反的次級渦對,但次級渦對始終未充分髮展。這是因為反射激波作用時氬氣柱界麵的Atwood數較小導緻氬氣柱界麵上產生的反嚮渦量較少。實驗結果充分錶明瞭氣體Atwood數對界麵不穩定性的髮展起到瞭較大的影響。
재수평방형격파관중대량충무막중기주계면(분별시SF6화아기)재반사격파작용하적불은정성발전진행료실험연구。기주계면채용사류기술형성,실험채용련속격광편광원조사류장,을이순작위시종입자,병용고속섭상궤대류장진행박섭,획득료입사격파이급반사격파공동작용하,량충불동기주계면적연화과정。실험결과표명,량충기주적Atwood수불동,계면연화속솔불동,반사격파도체전후적계면형태불동。SF6기주재입사격파작용하회산생량개비교명현적반향적와배결구,이아기주계면상유우산생적와량교소,와배결구병불명현。재반사격파작용하,SF6기주계면회출현명현적차급와대,이차차급와대적선전방향여초시와배결구적선전방향상반。대우아기주이언,재반사격파작용하수연야산생료여초시와배방향상반적차급와대,단차급와대시종미충분발전。저시인위반사격파작용시아기주계면적Atwood수교소도치아기주계면상산생적반향와량교소。실험결과충분표명료기체Atwood수대계면불은정성적발전기도료교대적영향。
The evolutions of the Richtmyer-Meshkov instability of two kinds of membrane-less heavy gas cylinder (SF6 and argon),under reshock condition with a specific reflected dis-tance,are experimentally studied in a horizontal square shock tube.Based on the jet technique, SF6 and argon gas cylinders are generated respectively to study the effect of Atwood number on the development of the Richtmyer-Meshkov instability.For the visualization of the flow,the tested gases are mixed with glycol droplets which are generated by the fog generator.Illuminated by a continuous laser sheet with a width of 80mm and a thickness of 1 mm,the interface mor-phologies after incident shock and reshock impact are captured in a single test run with the help of the high speed camera.The results show that different evolving rates and interface morphologies before and after reshock are observed for SF6 and argon gas cylinders due to the different Atwood numbers.For the same reflected end wall,the visible two reversed vortex rings are generated for the SF6 gas cylinder after the incident shock passage,which are not apparently observed for the argon gas cylinder because of less vorticity deposition on the interface.Moreover,after the re-shock impact,secondary vortex rings which have reversed rotating directions to the original vor-tex rings are quickly generated in the SF6 gas cylinder and dominate the flow field at the later stage,becoming the primary feature of the flow.However,in the argon gas cylinder,the second-ary vortex rings,though generated with opposite directions of rotation to the original ones,are not fully developed all the time due to the smaller Atwood number that results in less production of reversed baroclinic vorticity on the argon interface.The present results illustrate the pronounced influence of the Atwood number on the development of the Richtmyer-Meshkov instability.