CAJ | 학술논문

采用实验和大涡模拟对喷嘴出口雷诺数(Re=U0hρ/μ,其中U0为出口平均速度, h为平面喷嘴出口狭缝高度,ρ和μ分别为流体的密度与动力黏度)为25—10000,喷嘴间距L为4h—40h范围内的平面撞击流偏斜振荡特性进行了研究.通过对平面撞击流模拟和实验的结果进行比较,验证了数值模拟的可靠性,并对平面撞击流发生偏斜振荡的无因次参数(喷嘴间距L/h与出口雷诺数Re)范围进行划分,重点考察了湍流平面撞击流的偏斜振荡周期及速度-压力变化特征.研究结果表明大涡模拟能对平面撞击流的偏斜振荡进行有效预报;当平面撞击流发生周期性偏斜振荡时,特定点的压力与速度也发生周期性变化,且变化周期与偏斜振荡周期一致,偏斜振荡本质上是由速度-压力的周期性变化和转换引起的.
채용실험화대와모의대분취출구뢰낙수(Re=U0hρ/μ,기중U0위출구평균속도, h위평면분취출구협봉고도,ρ화μ분별위류체적밀도여동력점도)위25—10000,분취간거L위4h—40h범위내적평면당격류편사진탕특성진행료연구.통과대평면당격류모의화실험적결과진행비교,험증료수치모의적가고성,병대평면당격류발생편사진탕적무인차삼수(분취간거L/h여출구뢰낙수Re)범위진행화분,중점고찰료단류평면당격류적편사진탕주기급속도-압력변화특정.연구결과표명대와모의능대평면당격류적편사진탕진행유효예보;당평면당격류발생주기성편사진탕시,특정점적압력여속도야발생주기성변화,차변화주기여편사진탕주기일치,편사진탕본질상시유속도-압력적주기성변화화전환인기적.
@@@@The deflecting oscillation of planar opposed jets is experimentally studied and numerically simulated by large-eddy simulation (LES) at 25 Re 10000 (Re=U0hρ/μ, where U0 is the bulk velocity of the jet at the nozzle exit, h is the height of the slit of the planar nozzle, andρ and μ are the density and dynamic viscosity of fluid, respectively) and 4h L 40h, where L is the nozzle separation. The numerical results are validated by comparing with the experimental results of planar opposed jets. Maps of parameter space describing the deflecting oscillation of planar opposed jets at various nozzle separations and exit Reynolds numbers are presented. And the variation features of deflecting oscillation periods and velocity-pressure of turbulent planar opposed jets are primarily investigated. The results of the study show that the LES can effectively predict the deflecting oscillation of planar opposed jets. The velocity and pressure at specific points vary periodically while the deflecting oscillation of planar opposed jets happens. Furthermore, the variation periods of velocity and pressure are in accordance with the periods of the deflecting oscillation. In essence, the deflecting oscillation of planar opposed jets is caused by periodical variation and transformation of the velocity and pressure.