船舶力学
船舶力學
선박역학
JOURNAL OF SHIP MECHANICS
2013年
4期
327-335
,共9页
时素果%王国玉%陈广豪%张敏弟
時素果%王國玉%陳廣豪%張敏弟
시소과%왕국옥%진엄호%장민제
热力学效应%DPIV%空化形态%流速分布%涡量分布
熱力學效應%DPIV%空化形態%流速分佈%渦量分佈
열역학효응%DPIV%공화형태%류속분포%와량분포
thermal effect%DPIV%cavitation shape%velocity distribution%vorticity distribution
为了研究热力学效应对空化流动结构的影响,采用实验的方法研究了水温为6℃、25℃和45℃时绕水翼的非定常空化流场.利用高速全流场显示技术,观察了不同水温下绕水翼的空化流动形态,并利用数字粒子图像测速仪(DPIV)测量了其速度和涡量分布.结果表明:随着水温的升高,空穴区域减小,空穴长度减短.在相同的空化阶段,热力学效应对空泡的脱落周期影响较小,脱落周期基本不变.热力学效应对速度和涡量影响较大的区域主要集中在空化区域及其与主流区的交界面处.随着水温的升高,低速高脉动区域逐渐减小,且对应的速度值略有升高,导致速度梯度减小,湍流脉动强度降低.同时发现,涡量区域对应于流场中具有速度梯度的区域,上下涡量区域随着水温的升高减小,涡量值降低.
為瞭研究熱力學效應對空化流動結構的影響,採用實驗的方法研究瞭水溫為6℃、25℃和45℃時繞水翼的非定常空化流場.利用高速全流場顯示技術,觀察瞭不同水溫下繞水翼的空化流動形態,併利用數字粒子圖像測速儀(DPIV)測量瞭其速度和渦量分佈.結果錶明:隨著水溫的升高,空穴區域減小,空穴長度減短.在相同的空化階段,熱力學效應對空泡的脫落週期影響較小,脫落週期基本不變.熱力學效應對速度和渦量影響較大的區域主要集中在空化區域及其與主流區的交界麵處.隨著水溫的升高,低速高脈動區域逐漸減小,且對應的速度值略有升高,導緻速度梯度減小,湍流脈動彊度降低.同時髮現,渦量區域對應于流場中具有速度梯度的區域,上下渦量區域隨著水溫的升高減小,渦量值降低.
위료연구열역학효응대공화류동결구적영향,채용실험적방법연구료수온위6℃、25℃화45℃시요수익적비정상공화류장.이용고속전류장현시기술,관찰료불동수온하요수익적공화류동형태,병이용수자입자도상측속의(DPIV)측량료기속도화와량분포.결과표명:수착수온적승고,공혈구역감소,공혈장도감단.재상동적공화계단,열역학효응대공포적탈락주기영향교소,탈락주기기본불변.열역학효응대속도화와량영향교대적구역주요집중재공화구역급기여주류구적교계면처.수착수온적승고,저속고맥동구역축점감소,차대응적속도치략유승고,도치속도제도감소,단류맥동강도강저.동시발현,와량구역대응우류장중구유속도제도적구역,상하와량구역수착수온적승고감소,와량치강저.
In order to investigate the influence of the thermal effect on the unsteady cavitation structure, the unsteady characteristics of cavitating flows under 6℃, 25℃and 45℃around Clark-y hydrofoil are in-vestigated by experimental methods. A high-speed video camera is used to visualize the flow structures un-der different cavitation numbers. The digital particle image velocimetry (DPIV) is employed to measure the velocity and vorticity distribution. The results show that the cavity region becomes smaller and the cavity length is shorter with temperature increasing. But at the same cavitation regimes, the influence of the ther-mal effect on the cavity shedding cycle is small and the shedding cycle is basically the same. The region which shows larger influence of the thermal effect on the velocity and vorticity distribution is major in the cavitation region and the interface between the cavitation region and main free-stream region. The high-fluctuating region with lower velocity becomes smaller and the specific velocity value increases slightly with temperature increasing. It results that the velocity gradient decreases and the turbulence fluctuating in-tensity decreases with temperature increasing. It can be also found that the vorticity region is corresponding to the region which has higher velocity gradient, the upper and lower vorticity region and its value decrease with temperature increasing.