What is a biofluid?

What is a biofluid?

A biofluid is a water-based liquid that contains solutes essential to body functions, thus makes highly variable the chemical composition of them, as it is dependent on which portion of body is located. The concept of fluid is often confused with that of liquid, but in fact, a fluid can be both liquid and gas. They are substances with weak attraction between their molecules. We can classify fluids according to their rheological behaviours as observed in shear stress-shear rate plots. three main groups: newtonians, non-newtonians, and ideal fluids1.


Viscosity is a distinctive property of fluids and is defined as the opposition of a fluid to tangential deformations. In Newtonians case, they are characterized by a viscosity that is independent of shear rate. Water and oil are examples of Newtonian fluids2.

Non Newtonians

In non newtonians case, the shear stress in not directly proportional to the rate of shear strain or velocity gradient. Presence of clays, polymers, and several additives in drilling fluids creates non Newtonian fluids2.

Ideal fluids

These types of fluids are incompressible and posses no viscosity. Such a fluid is only an imaginary fluid. All existing fluids have some viscosity1. Of all the cryogenic fluids, helium exhibits behavior that most nearly approximates that of an ideal fluid3.





  1. What is Fluid?- Phases, Types, Properties, and Flow – Engineering Choice. (n.d.). Retrieved October 14, 2022, from https://www.engineeringchoice.com/what-is-fluid/
  2. Rehm, B., & Haghshenas, A. (2012). Flow Drilling: Underbalance Drilling with Liquid Single-Phase Systems. Underbalanced Drilling: Limits and Extremes, 39–108. https://doi.org/10.1016/B978-1-933762-05-0.50009-7
  3. van Sciver, S. W. (1986). Helium as a Classical Fluid. Helium Cryogenics, 53–76. https://doi.org/10.1007/978-1-4899-0499-7_3

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