Biofluid dynamics is also an example of a biological fluid. Types of Fluids Fluids can be classified into four basic types. They are: An Ideal Fluid is a fluid that has no viscosity, means it will offer no resistance, pragmatically this type of fluid does not exist. It is incompressible in nature. Real fluids are compressible in nature. They offer some resistance and thus have viscosity. All Fluids existing are real fluids. A Newtonian Fluid is a fluid whose viscous shear stresses (acting between different layers of fluid and between the fluid layer and surface over which it is flowing) are directly
Incompressible flow to ensure incompressible "flow". When we speak of the partial derivative of the density with respect to time, we refer to this rate of change within a control volume of "fixed position". By letting the partial time derivative of the density be non-zero, we are not restricting ourselves to incompressible "fluids", because the density can change as observed from a fixed position as fluid flows through the control volume. This approach maintains generality, and not requiring that the partial time derivative of the density vanish illustrates that compressible fluids can still undergo incompressible flow. What interests us is the change