In our thought experiment we can force fluid to flow through this die at a certain volume per unit time or volumetric flow rate Q and allow no drag with the walls. This is a total slip condition so no shear will be applied to the fluid. The fluid will travel faster as the geometry contracts so the velocity V(l) in a plane across the geometry simply depends upon the area at any length / [Pg.272]

Now the extension rate e in the geometry is given by the rate of change of velocity with distance [Pg.273]

Evaluating the integral and using the extension rate we obtain the following expression [Pg.274]

In the opposed jets design fluid is sucked or pumped into a beaker. The profile which develops is dominantly extensional. In the profiled slot design a rectangular channel is designed such that in the total slip condition an extensional flow develops with a constant rate. The pressure is measured at the stagnation point. Other designs include the open syphon, where fluid is sucked from a beaker through a nozzle which is [Pg.274]

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