Shear stress induced on fluid in centrifugal pump

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 October 8, 2012, 21:31 Shear stress induced on fluid in centrifugal pump #1 New Member   Kimberley Join Date: Sep 2012 Posts: 2 Rep Power: 0 Sponsored Links Hi, Im completing a study on an artificial heart pump. I have completed a CFD model in CFX, however i am confused as to how to determine the shear stress induced on the blood. Predefined expressions gives Wall Shear Stress, but i dont think this is what i need. Do i need to define my own expression? And does TauZY = viscosity * (dv/dz + dw/dy) be the correct expression for shear stress on the fluid? Any insight much appreciated

 September 30, 2016, 02:20 #2 Member   kastarkas Join Date: Aug 2016 Posts: 36 Rep Power: 3 Its alomost 4 years old..but still ...i hope you might have solved the problem and travelled way beyond that...

 September 30, 2016, 11:39 #3 Senior Member   Join Date: Jun 2009 Posts: 679 Rep Power: 15 In CFD-Post, you can create user defined variables, and write expressions for the different components of the stress tensor, say: sigma_xx, tau_xy, ... Keep in mind CFD-Post provides the gradient of the velocity field, and you can use them as in Velocity u.Gradient X (du/dx). Also, to clarify the confusion between Wall Shear Stress and tau_yz. Wall Shear Stress is the tangential force per unit area on the surface, i.e. the tangential component of the product between the stress tensor and the normal unit vector. tau_yz is the component in yz plane of the stress tensor which only defines the state of stress in space, and a surface must be defined to compute the force per unit area on such surface. For more information, https://en.wikipedia.org/wiki/Stress_(mechanics) Hope the above helps,

 Tags blood pump, cfd, cfx, pump, shear stress

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