ABE-KONDOH-NAGANO,ABID,YANG-SHIH and LAUNDER-SHARMA low-Reynolds number turbulence models were applied to simulating unsteady turbulence flow around a square cylinder in different phases flow field and time-averaged u...ABE-KONDOH-NAGANO,ABID,YANG-SHIH and LAUNDER-SHARMA low-Reynolds number turbulence models were applied to simulating unsteady turbulence flow around a square cylinder in different phases flow field and time-averaged unsteady flow field.Meanwhile,drag and lift coefficients of the four different low-Reynolds number turbulence models were analyzed.The simulated results of YANG-SHIH model are close to the large eddy simulation results and experimental results,and they are significantly better than those of ABE-KONDOH-NAGANO,ABID and LAUNDER-SHARMR models.The modification of the generation of turbulence kinetic energy is the key factor to a successful simulation for YANG-SHIH model,while the correction of the turbulence near the wall has minor influence on the simulation results.For ABE-KONDOH-NAGANO,ABID and LAUNDER-SHARMA models satisfactory simulation results cannot be obtained due to lack of the modification of the generation of turbulence kinetic energy.With the joint force of wall function and the turbulence models with the adoption of corrected swirl stream,flow around a square cylinder can be fully simulated with less grids by the near-wall.展开更多
文章使用超大涡模拟(very large eddy simulation,VLES)方法耦合离散相模型对液体射流在横向气流中雾化过程进行模拟,并对比多套网格尺度下不同湍流模型的预测结果。结果表明,VLES方法能够较为准确地预测横向射流的基本形态及参数。相...文章使用超大涡模拟(very large eddy simulation,VLES)方法耦合离散相模型对液体射流在横向气流中雾化过程进行模拟,并对比多套网格尺度下不同湍流模型的预测结果。结果表明,VLES方法能够较为准确地预测横向射流的基本形态及参数。相对其他湍流模型在不同网格尺度下模拟结果波动明显,VLES方法对网格尺寸敏感度较低,并在模拟流场流动细节方面能够捕捉到更多液柱破碎的表面结构,较雷诺平均(Reynolds-averaged Navier-Stokes,RANS)模拟方法有显著优势,且计算量比大涡模拟(large eddy simulation,LES)方法大大降低,在工程实际运用中是一种颇具潜力的数值研究方法。展开更多
为了研究文丘里空化器内非定常空化流动诱导的能量特性,构建了一种评估空化能量指标的物理模型,并基于Wall-Adapting Local Eddy-Viscosity(WALE)亚格子模型的大涡模拟方法(LES-WALE)和Schnerr-Sauer空化模型,对文丘里空化器内的空化流...为了研究文丘里空化器内非定常空化流动诱导的能量特性,构建了一种评估空化能量指标的物理模型,并基于Wall-Adapting Local Eddy-Viscosity(WALE)亚格子模型的大涡模拟方法(LES-WALE)和Schnerr-Sauer空化模型,对文丘里空化器内的空化流动特性进行了数值分析,研究了3种空化阶段下(σ为0.76,0.51和0.26)文丘里空化器内空化能量分布规律.研究表明:LES-WALE湍流模型和Schnerr-Sauer空化模型联合的数值计算方法可以对文丘里空化器内片状空化对称脱落及云空化溃灭的细节进行精确捕捉;随着空化数的降低,文丘里空化器内空化能量呈现范围及对应数值逐渐增大,在不同空化阶段下,计算域内空化能量的极值发生在片状空穴末端位置处;沿着整个文丘里空化器壁面,其喉部与扩散管连接处存在的空化能量最高,表明该处极易受到空化的破坏作用.研究结果为以文丘里空化器为典型代表的水力空化装置空化能量特性研究提供了一种有效的数值计算方法及能量评估指标.展开更多
基金Project(2006BAJ04B04)supported by the National Science and Technology Pillar Program in the Eleventh Five-year Plan PeriodProject(2006AA05Z229)supported by the National High Technology Research and Development Program of China+1 种基金Project supportedby the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education MinistryProject(06wk3023)supported by Hunan Science and Technology Office
文摘ABE-KONDOH-NAGANO,ABID,YANG-SHIH and LAUNDER-SHARMA low-Reynolds number turbulence models were applied to simulating unsteady turbulence flow around a square cylinder in different phases flow field and time-averaged unsteady flow field.Meanwhile,drag and lift coefficients of the four different low-Reynolds number turbulence models were analyzed.The simulated results of YANG-SHIH model are close to the large eddy simulation results and experimental results,and they are significantly better than those of ABE-KONDOH-NAGANO,ABID and LAUNDER-SHARMR models.The modification of the generation of turbulence kinetic energy is the key factor to a successful simulation for YANG-SHIH model,while the correction of the turbulence near the wall has minor influence on the simulation results.For ABE-KONDOH-NAGANO,ABID and LAUNDER-SHARMA models satisfactory simulation results cannot be obtained due to lack of the modification of the generation of turbulence kinetic energy.With the joint force of wall function and the turbulence models with the adoption of corrected swirl stream,flow around a square cylinder can be fully simulated with less grids by the near-wall.
文摘为了研究文丘里空化器内非定常空化流动诱导的能量特性,构建了一种评估空化能量指标的物理模型,并基于Wall-Adapting Local Eddy-Viscosity(WALE)亚格子模型的大涡模拟方法(LES-WALE)和Schnerr-Sauer空化模型,对文丘里空化器内的空化流动特性进行了数值分析,研究了3种空化阶段下(σ为0.76,0.51和0.26)文丘里空化器内空化能量分布规律.研究表明:LES-WALE湍流模型和Schnerr-Sauer空化模型联合的数值计算方法可以对文丘里空化器内片状空化对称脱落及云空化溃灭的细节进行精确捕捉;随着空化数的降低,文丘里空化器内空化能量呈现范围及对应数值逐渐增大,在不同空化阶段下,计算域内空化能量的极值发生在片状空穴末端位置处;沿着整个文丘里空化器壁面,其喉部与扩散管连接处存在的空化能量最高,表明该处极易受到空化的破坏作用.研究结果为以文丘里空化器为典型代表的水力空化装置空化能量特性研究提供了一种有效的数值计算方法及能量评估指标.
