ABSTRACT
The fluid motion is governed by physical laws that, when mathematically expressed, allow all fluid parameters to be determined at every point in space. However, in fluid mechanics, there are cases where it is desirable to have the reference frame move either with the fluid body or with a particle moving inside the fluid. Physics-based models in fluid dynamics involve solving governing equations for fluid flow, heat transfer, chemical species transport, and related phenomena. The fluid’s density can be dependent on temperature or pressure. Typically, the food industry deals with incompressible fluids or fluids that may only have temperature dependency. Along with the density, viscosity is an important property that characterizes the flow resistances in fluid flow problems, and it is the property that determines the rheology of the material. Viscosity relates the shear stress in the fluid to the rate of deformation of the fluid, and it often has a complex, non-linear behavior.
