# Fluid Shear Stress

| Last updated: March 8, 2022

## What Does Fluid Shear Stress Mean?

Fluid shear stress refers to the unit area amount of force that acts on a given fluid parallel to a small element of the surface. This occurs due to the component’s force vector, which is parallel to the cross section.

Fluid shear stress is in contradiction to the normal stress arising from force vectors. These force vectors are perpendicular to the material’s cross section, where it acts.

Fluid shear stress is also an important factor in determining stem cell fate. The technique of application, direction pattern and magnitude all influence cell fate and are what produce different patterns and proliferation.

Fluid shear produces mechanical stimuli at a cellular level. There are some fluids, however, that do not depend on fluid shear stress rate history. Time-independent and non-Newtonian fluids tend to be divided into shear thickening, shear thinning, and typical Newtonian fluids. For fluid shear stress to be calculated accurately, the elements should be very small. The greatest source of stress, in this case, is fluid viscosity.

## Corrosionpedia Explains Fluid Shear Stress

In a flow within a straight container or vessel, fluids do not move at identical velocity at each point within the vessel. In such a case, the fluid's flow is slowest near the vessel wall and quickest at its focal area. The fluid velocity assumes a laminar flow-like profile (or "parabolic"). This kind of flow is produced by friction within the vessel wall and is associated with fluid viscosity.

Fluids moving along a solid boundary or surface are bound to incur a shear stress from friction with that given boundary. The no-slip condition reinforces that the fluid speed at the boundary, when relative to the boundary, is always zero. However, at a certain height from the boundary, flow speed has to be equal that of the fluid. The region between the boundary and the height from the boundary at which flow speed is equal to that of the fluid is called the boundary layer.

For Newtonian fluids in laminar flow, shear stress is proportional to the strain rate that may be in the fluid—which is where viscosity is the constant proportionality. Although, for non-Newtonian fluids, viscosity is not constant; shear stress acts on the boundary as a result of this loss of velocity.

Considering the medium used, shear stress could cause a significant change in fluid flow between layers. Studying and understanding this phenomenon makes it possible to implement it in designing, monitoring, and controlling systems that typically include electronics for a wide range of applications in different fields—such as automotive, aerospace, energy and industrial processing.

In sum, fluid shear stress is a tangential force produced by friction as a result of flowing fluid. Fluid shear stress' magnitude depends on the fluid velocity when moving from and around the vessel; and its rate should be monitored and accurately measured to prevent stress—which causes corrosion. 