TUFLOW General Discussion: Difference between revisions
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τ=τ_0+k(du/dy)^n
It should be seen that where Ƭ0=0, the Herschel-Bulkley equation is the same as the power law model. If n is 1, then the Herschel-Bulkley equation is the same as the Bingham Plastic model. If Ƭ0=0 and n =1, then the Herschel-Bulkley equation is the same as the Newtonian fluid approach. By using the Herschel-Bulkley equation as a Newtonian model, it does allow you to define the viscosity coefficient for the fluid. In your case you’ll need to convert the viscosity from centiStokes to Pa S (if using an N value of 1). You can then define the fluid density using the <font color="blue"><tt>Density of Water</tt></font> command you mention.
You can test this out using the following commands.
<font color="blue"><tt>Viscosity Formulation </tt></font><font color="red"><tt>== </tt></font>Non-Newtonian<br>
<font color="blue"><tt>Viscosity Coefficients </tt></font><font color="red"><tt>== </tt></font>0.001, 1, 0.0, 1000, 0
This uses a n value of 1, a Ƭ0=0 and a viscosity coefficient of 0.001 Pa S which is a typical viscosity of water at 20 ℃. This should give comparable outputs to a standard TUFLOW model without the Non-Newtonian functionality.
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