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Nonlinear Taylor stability of viscoelastic fluids
Authors:C. F. Chan Man Fong
Affiliation:(1) Dept. of Mathematics, University of Reading, Reading, England
Abstract:Using Stuart's energy method, the torque on the inner cylinder, for a second order fluid, in the supercritical regime is calculated. It is found that when the second normal stress difference is negative, the flow is more stable than for a Newtonian fluid and the torque is reduced. If the second normal stress difference is positive, then the flow is more stable and there is no torque reduction. Experimental data related to the present work are discussed.Nomenclature a amplitude of the fundamentals - Aij(1), Aij(2) first and second Rivlin-Ericksen tensors - d r2r1 - D d/dx - E 
$$frac{{2pi r_1 r_o eta _0^2 h}}{{rho d^2 }}left( {1 - frac{{I_1 I_4 }}{{I_3 }}} right)$$
- F 
$$frac{{2pi r_1^2 r_o eta _0^2 T_c h}}{{rho d^3 }}frac{{I_1 I_4 }}{{I_3 }}$$
- gij metric tensor - G torque on the inner cylinder in the supercritical regime - h height of the cylinders - k0 beta/rgrd2 - k1 gamma/rgrd2 - I1 
$$mathop smallint limits_{ - tfrac{1}{2}}^{tfrac{1}{2}}  - uupsilon  dx + left( {k_o  + 2k_1 } right)r_1 /dmathop smallint limits_{ - tfrac{1}{2}}^{tfrac{1}{2}}  upsilon (D^2  - lambda ^2 ) u dx$$
- I2 
$$mathop smallint limits_{ - tfrac{1}{2}}^{tfrac{1}{2}}  [(D^2  - lambda ^2 ) u]^2  dx$$
- I3 
$$begin{gathered}  (1 + 2k_0 lambda ^2 )(mathop smallint limits_{ - tfrac{1}{2}}^{tfrac{1}{2}}  - uv dx)^2  - (1 + k_0 lambda ^2 )mathop smallint limits_{ - tfrac{1}{2}}^{tfrac{1}{2}} u^2 v^2  dx +  hfill    + left( {k_0  + 3k_1 } right)mathop smallint limits_{ - tfrac{1}{2}}^{tfrac{1}{2}}  - uv dxmathop smallint limits_{ - tfrac{1}{2}}^{tfrac{1}{2}} u^2 v dx +  hfill    + k_0 mathop smallint limits_{ - tfrac{1}{2}}^{tfrac{1}{2}} (2u^3 v + 4uv Du Dv + 2u^2 (Dv)^2  +  hfill    +  v^2 (Du)^2 )dx + k_1 mathop smallint limits_{ - tfrac{1}{2}}^{tfrac{1}{2}} (u^2 (Dv)^2  + v^2 (Du)^2  + 2uv Dv Dv + 3u^3 v) dx hfill  end{gathered}$$
- I4 
$$(1 - 2k_0 lambda ^2 )mathop smallint limits_{ - tfrac{1}{2}}^{tfrac{1}{2}}  - uv dx + (k_0  - 2k_1 )mathop smallint limits_{ - tfrac{1}{2}}^{tfrac{1}{2}} u^2  dx$$
- r1, r2 radii of inner and outer cylinders respectively - r0 1/2(r1+r2) - R Reynolds number OHgr1r1drgr/eegr0 - Rc critical Reynolds number - T Taylor number r1OHgr12d3rgr2/eegr02*) - Tc critical Taylor number - u1, v1, w1 Fundamentals of the disturbance - ui, vi, wi, (i>1) harmonics - 
$$bar v$$
mean velocity (not laminar velocity) - u –u1/ar1OHgr1 - v v1/Rar1OHgr1 - x (r–r0)/d - beta,gamma material constants - eegr0 viscosity - lambda wave number agrd - rgr density - OHgr1 angular velocity of inner cylinder - sim tilde denotes complex conjugate
Keywords:
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