What is extensional flow?
The simplest definition of an extensional flow is that it is a defor- mation that involves stretching along streamlines.
How is extensional viscosity measured?
Extensional viscosity can be measured using rheometers that apply extensional stress. Acoustic rheometer is one example of such devices.
What is simple shear flow?
In simple shear flow, the vast majority of polymer solutions are pseudoplastic in nature, which means that the viscosity is decreased as the shear rate is increased. The viscosity related to this type of flow is shear-thickening viscosity. In other words, the fluid has dilatant behavior.
What is shear flow in fluids?
In fluid mechanics, the term shear flow (or shearing flow) refers to a type of fluid flow which is caused by forces, rather than to the forces themselves. In a shearing flow, adjacent layers of fluid move parallel to each other with different speeds. Viscous fluids resist this shearing motion.
Where does the maximum shear flow occur?
The maximum shear stress occurs at the neutral axis and is zero at both the top and bottom surface of the beam. Shear flow has the units of force per unit distance.
What is steady shear flow?
condition under steady shear flow, where the separated. phases have almost the same viscosity.
What is the difference between pure shear and simple shear?
In mechanics and geology, pure shear is a three-dimensional homogeneous flattening of a body. It is an example of irrotational strain in which body is elongated in one direction while being shortened perpendicularly. Pure shear is differentiated from simple shear in that pure shear involves no rigid body rotation.
What is free shear flow?
Abstract. Turbulent free shear flows occur if there are no walls directly at the flow. Figure 22.1 shows some examples: a free jet, a buoyant jet, a mixing layer with the free jet–boundary flow as a special case, and a wake flow. The corresponding laminar flows are treated in Sects.
What is a shear layer?
A shear layer is a thin region of concentrated vorticity across which the tangential velocity component varies greatly. An example is the constant-vorticity layer given by parallel 2D flow u x , y = U y , v x , y = 0 , where U is as shown in Figure 4a.
What type of plate movement causes extension?
Divergent plate boundaries are zones where plates split into two or more smaller plates that move apart and the dominant stress field is extension.