【摘 要】
：
Recently,a new definition,called Rortex,was proposed to quantify the purely rotational motion of fluids.In this work,based on the DNS data,the Rortex is used to assess and visualize the rotational motion and structure of the vortex in swirling jets in com
【机 构】
：
Institute of Nuclear and New Energy Technology, Collaborative Innovation Center of Advanced Nuclear
论文部分内容阅读
Recently,a new definition,called Rortex,was proposed to quantify the purely rotational motion of fluids.In this work,based on the DNS data,the Rortex is used to assess and visualize the rotational motion and structure of the vortex in swirling jets in comparison with other kinds of vortex criteria,including Q,λ2,vorticity and Ω criteria.The Rortex vector,Ω,Q and λ2 criteria are found to be better than the vorticity criterion for the vortex core identification.The vector triangle formed by the Rortex R,the nonrotational shear S,and the vorticity Ωv is analyzed to give mechanical explanations,especially of the effect of the non-rotational shear on the rotation of fluids.In addition,the probability density distributions (PDF) of the Rortex R,the nonrotational shear S,and the vorticity Ωv are computed.The peak value of the PDF of the vorticity could be used to explain the pure rigid rotation effect and the combination effects of the rigid rotation and the non-rotational shear.
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