Shear stress tensor and specific shear viscosity of hot hadron gas in nuclear collisions

2022 ◽  
Vol 105 (1) ◽  
Author(s):  
Zhidong Yang ◽  
Rainer J. Fries
Keyword(s):  
Shear Stress ◽  
Stress Tensor ◽  
Shear Viscosity ◽  
Nuclear Collisions ◽  
Hadron Gas ◽  
Shear Stress Tensor

scholarly journals Quantification of shear viscosity and wall slip velocity of highly concentrated suspensions with non-Newtonian matrices in pressure driven flows

2021 ◽  
Author(s):  
Patrick Wilms ◽  
Jan Wieringa ◽  
Theo Blijdenstein ◽  
Kees van Malssen ◽  
Reinhard Kohlus
Keyword(s):  
Shear Stress ◽  
Liquid Phase ◽  
Shear Rate ◽  
Shear Viscosity ◽  
Slip Velocity ◽  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Wall Slip ◽  
Flow Index ◽  
Concentrated Suspensions

AbstractThe rheological characterization of concentrated suspensions is complicated by the heterogeneous nature of their flow. In this contribution, the shear viscosity and wall slip velocity are quantified for highly concentrated suspensions (solid volume fractions of 0.55–0.60, D4,3 ~ 5 µm). The shear viscosity was determined using a high-pressure capillary rheometer equipped with a 3D-printed die that has a grooved surface of the internal flow channel. The wall slip velocity was then calculated from the difference between the apparent shear rates through a rough and smooth die, at identical wall shear stress. The influence of liquid phase rheology on the wall slip velocity was investigated by using different thickeners, resulting in different degrees of shear rate dependency, i.e. the flow indices varied between 0.20 and 1.00. The wall slip velocity scaled with the flow index of the liquid phase at a solid volume fraction of 0.60 and showed increasingly large deviations with decreasing solid volume fraction. It is hypothesized that these deviations are related to shear-induced migration of solids and macromolecules due to the large shear stress and shear rate gradients.

The accelerated fully rough turbulent boundary layer

1977 ◽  
Vol 82 (3) ◽  
pp. 507-528 ◽  
Author(s):  
Hugh W. Coleman ◽  
Robert J. Moffat ◽  
William M. Kays
Keyword(s):  
Boundary Layer ◽  
Shear Stress ◽  
Turbulent Boundary Layer ◽  
Pressure Gradient ◽  
Stress Tensor ◽  
Skin Friction ◽  
Shape Factor ◽  
Reynolds Shear Stress ◽  
Smooth Wall ◽  
Mean Velocity

The behaviour of a fully rough turbulent boundary layer subjected to favourable pressure gradients both with and without blowing was investigated experimentally using a porous test surface composed of densely packed spheres of uniform size. Measurements of profiles of mean velocity and the components of the Reynolds-stress tensor are reported for both unblown and blown layers. Skin-friction coefficients were determined from measurements of the Reynolds shear stress and mean velocity.An appropriate acceleration parameterKrfor fully rough layers is defined which is dependent on a characteristic roughness dimension but independent of molecular viscosity. For a constant blowing fractionFgreater than or equal to zero, the fully rough turbulent boundary layer reaches an equilibrium state whenKris held constant. Profiles of the mean velocity and the components of the Reynolds-stress tensor are then similar in the flow direction and the skin-friction coefficient, momentum thickness, boundary-layer shape factor and the Clauser shape factor and pressure-gradient parameter all become constant.Acceleration of a fully rough layer decreases the normalized turbulent kinetic energy and makes the turbulence field much less isotropic in the inner region (forFequal to zero) compared with zero-pressure-gradient fully rough layers. The values of the Reynolds-shear-stress correlation coefficients, however, are unaffected by acceleration or blowing and are identical with values previously reported for smooth-wall and zero-pressure-gradient rough-wall flows. Increasing values of the roughness Reynolds number with acceleration indicate that the fully rough layer does not tend towards the transitionally rough or smooth-wall state when accelerated.

Rheological Behavior and Extrudate Swell of Polypropylene/Silicon Carbide Composites

2013 ◽  
Vol 747 ◽  
pp. 595-598 ◽  
Author(s):  
Apaipan Rattanapan ◽  
Nuttaphong Sornsuwit ◽  
Rapeephun Dangtungee
Keyword(s):  
Silicon Carbide ◽  
Shear Stress ◽  
Shear Viscosity ◽  
Rheological Behavior ◽  
Sem Analysis ◽  
Elongation Rate ◽  
Capillary Rheometer ◽  
Extrudate Swell ◽  
Elongation Viscosity ◽  
Sic Composites

The rheological behavior and extrudate swell of polypropylene (PP)/silicon carbide (SiC) composites were investigated. Polypropylene-grafted-maleic anhydride (PP-g-MA) was introduced into blending system as a compatibilizer. The effect of silicon carbide loading and surface modification on the rheological behavior of PP/SiC composites were studied using a capillary rheometer and SEM analysis. The results showed that the composites exhibit pseudoplastic behavior as the shear stress and extrudate swell increased with increasing shear rate, while shear viscosity decreased. Moreover, an increasing elongation rate leads to reduce elongation viscosity. The addition of PP-g-MA in PP/SiC composites has significantly decreased the apparent shear stress, apparent shear viscosity and percentage of extrudate swell.

Coupling between the mesoscopic dynamics and shear stress of a room-temperature ionic liquid

2018 ◽  
Vol 20 (26) ◽  
pp. 17809-17817 ◽  
Author(s):  
Tsuyoshi Yamaguchi
Keyword(s):  
Shear Stress ◽  
Ionic Liquid ◽  
Domain Structure ◽  
Shear Viscosity ◽  
Room Temperature ◽  
Room Temperature Ionic Liquid

Shear viscosity of an ionic liquid is governed by the dynamics of the charge-alternation mode irrespective of the presence of the domain structure.

Stress

2020 ◽  
pp. 9-28
Author(s):  
Adrian P. Sutton
Keyword(s):  
Shear Stress ◽  
Stress Tensor ◽  
Elastic Energy ◽  
Functional Derivative ◽  
Shear Stresses ◽  
Mechanical Equilibrium ◽  
Normal Stresses ◽  
Atomic Interactions ◽  
Insightful Analysis ◽  
Von Mises

The concept of stress is introduced in terms of interatomic forces acting through a plane, and in the Cauchy sense of a force per unit area on a plane in a continuum. Normal stresses and shear stresses are defined. Invariants of the stress tensor are derived and the von Mises shear stress is expressed in terms of them. The conditions for mechanical equilibrium in a continuum are derived, one of which leads to the stress tensor being symmetric. Stress is also shown to be the functional derivative of the elastic energy with respect to strain,which enables the stress tensor to be derived in models of interatomic forces. Adiabatic and isothermal stresses are distinguished thermodynamically and anharmonicity of atomic interactions is identified as the reason for their differences. Problems set 2 containsfour problems, one of which is based on Noll’s insightful analysis of stress and mechanical equilibrium.

The effective film viscosity coefficients of a thin floating fluid layer

1997 ◽  
Vol 344 ◽  
pp. 335-337 ◽  
Author(s):  
ALASTAIR D. JENKINS ◽  
KRISTIAN B. DYSTHE
Keyword(s):  
Shear Stress ◽  
Thin Layer ◽  
Tangential Stress ◽  
Constitutive Relation ◽  
Shear Viscosity ◽  
Fluid Layer ◽  
Tangential Velocity ◽  
Two Dimensional ◽  
Viscosity Coefficients ◽  
Lower Fluid

We derive a constitutive relation, relating the tangential stress, tangential velocity, thickness h, and viscosity μ, for a thin layer of Newtonian fluid on top of a fluid substrate. We find that the upper layer exerts a viscous tangential shear stress on the lower fluid, behaving as if it were a film with a two-dimensional shear viscosity equal to μh, and a dilatational viscosity 3μh.

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