On the detection, measurement, and characterization of slip-velocity in Couette-rheology involving viscoelastic liquids

摘要: We present a robust calculation leading to experimentally convenient and accurate ways of detecting, measuring, characterizing velocity-slippage in viscoelastic-fluids, unlike previous inaccurate Mooney-type techniques. Herein, the unsteady Navier-Stokes equation for viscoelastic-fluid is solved while highlighting rheological ramification. Our results emphasize phase-lags amongst shear stresses strains, key output used differing slip-types. The viscoelastic fluid non-aging isothermal, we obtain an exact solution non-trivial flow profile, without assuming linear Couette profile as customarily used. Moreover, Navier-type slip boundary condition considered. This approach similar that done our earlier paper [Azese, “Measurement characterization slippage slip-law using rigorous analysis dynamics oscillating rheometer: Newtonian fluid,” Phys. Fluids 30, 023103 (2018)] where instead it was fluid. Accordingly, sample trapped Couette-gap, one them stationary other steadily with amplitude Re (Reynolds-number) angular speed Ω = Ro (Roshko number), thus Couette-rheometry. showcase alternative way steady-periodic solution, matching long-time obtained paper. this case also use method version, later obtaining velocity stress at walls. Interestingly, note influence Re, Ro, Wi (Weissenberg Number) on analysis. equations plots presented evidently show slip. conclude reverse algorithms, Fourier-transform, Lissajous-figures, Mooney-like procedures, capable reproducing slip-parameters, systematic measurement-and-characterization slip, useful calibration devices.