Shear stress induced on fluid in centrifugal pump
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 :) 
Its alomost 4 years old..but still ...i hope you might have solved the problem and travelled way beyond that...

In CFDPost, 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 CFDPost 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, 
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