What is Fluid Dynamics?

Application of Fluid Dynamics

Fluid dynamics is "an area of applied science concerned with the movement of liquids and gases," according to the American Heritage Dictionary. Fluid dynamics is one of the two branches of fluid mechanics, which is the study of fluids and how their strength affects them. (The other category is fluid statics which deals with fluids at rest.)

Fluid Dynamics is a sub-discipline of fluid mechanics that deals with fluid movement in motion. There are several branches of fluid dynamics, aerodynamics, and hydrodynamics few in the popularly recognized fluid mechanics. This covers a wide variety of applications, such as calculating force & moments, determining the mass flow rate of oil through pipelines, forecasting weather patterns, understanding interstellar nebulae, and modeling.

Scientists in a variety of areas research fluid dynamics. Fluid dynamics offers tools to study the evolution of planets, ocean tides, weather patterns, plate tectonics, and also blood circulation. Some of the important technological applications of fluid dynamics include rocket engines, wind turbines, oil pipelines, and air conditioning systems.

What is Flow?

The movement of liquids and gases, in general, is referred to as "flow," a term that explains how fluids behave and how they interact with their natural environment — for example, water flowing through a canal or pipe or over a surface. Flow may be either slow or unstable. In his lecture on elementary fluid dynamics (University of Kentucky, 2009), J. M. McDonough, Professor of Engineering at the University of Kentucky, writes, "If all the properties of the flow are independent of time, the flow is constant; otherwise it is unsteady." That is, the steady flow does not change over time.

An example of steady flow will be the flow of water through the pipe at a constant rate. On the other side, a flood or stream from an old-fashioned hand pump is an example of a steady flow.

Flow can be either laminar or turbulent. The laminar flow is smoother, while the turbulent flow is more chaotic. One important factor in deciding the flow status of the fluid is its viscosity or thickness, where higher viscosity increases the propensity of the flow to be laminar. Patrick McMurtry, an engineering professor at the University of Utah, explains the difference in his online class notes, "Observations About Turbulent Flows" (University of Utah, 2000), writing, "By laminar flow, we are usually referring to a smooth, steady flow of fluid in which any caused disturbances are dampened by relatively strong viscous forces.

What are The Dynamics of Computational Fluid? 

Computational fluid dynamics is a fluid mechanics branch that uses numerical modeling and algorithms to solve and interpret fluid flow problems. High-speed supercomputers are used to measure what is needed to simulate the interaction of liquids and gases. 

Application of fluid mechanics 

Fluid Dynamics Can Be Seen in The Following Ways -

  • Fluid dynamics is used to measure the forces acting on the aircraft. 

  • This is used to track content flow levels, such as oil from pipelines. 

  • This may also be used in traffic engineering (traffic viewed as a continuous flow of liquids).

Equations in Fluid Dynamics: Bernoulli’s Equation -

 = P/ρ + g z + v2/2 = k

= P/ρg + z + v2 / 2g = k

= P/ρg + v2 / 2g + z = k


P/ρg  is the pressure head or pressure energy per unit weight fluid

v2 / 2g is the kinetic head or kinetic energy per unit weight

z is the potential head or potential energy per unit weight

P is the Pressure

ρ is the Density

K is the Constant

The Bernoulli equation is different for isothermal as well as adiabatic processes.

dP/ρ + VdV + gdZ = 0

∫( dP/ρ +VdV + gdZ) = K

∫dPρ + V22 + gZ = K


Z is the elevation point

ρ is the density of the fluid

The equation can also be written as,



q is the dynamic pressure

PO is the total pressure

P is the static pressure

Alternative Terms for Fluid Mechanics 

Fluid dynamics is also often referred to as hydrodynamics, but this is more of a historical term. In the 20th century , the term "fluid dynamics" has been much more widely used. 

Technically, it would be more fitting to say that hydrodynamics is when fluid dynamics are applied to fluids in motion and aerodynamics when fluid dynamics are applied to gasses in motion. 

For action, however, advanced subjects such as hydrodynamic stability and magnetohydrodynamics use the "hydro-" suffix only when applying these definitions to the motion of gases.

FAQ (Frequently Asked Questions)

1. Explain Fluid Dynamics?

Fluid dynamics is a study of fluid movements, including their interactions as two fluids, come into contact with each other. In this context, the term "fluid" refers to either liquid or gas. This is a macroscopic, mathematical approach to the study of these interactions on a broad scale, treating the fluids as a continuum of matter, and usually ignoring the fact that the liquid or gas is made up of individual atoms. 

Fluid dynamics is one of the two primary branches of fluid mechanics, while the other branch is fluid statics, the study of fluids at rest. (Unsurprisingly, fluid statics can be considered to be a little less thrilling much of the time than fluid dynamics.)

2. Give a brief on Basic Fluid Principles?

Principles of Essential Fluid 

Fluid principles that are used in fluid statics often come into play when studying fluid that is in motion. Perhaps the first definition in fluid mechanics is that of buoyancy, discovered in ancient Greece by Archimedes. 

For the flow of fluids, the density and pressure of fluids are also essential to understanding how they interact. Viscosity determines how the liquid is resistant to change, so it is also essential to study the movement of the liquid. Here are some of the variables that appear in these analyzes: 

The viscosity of the bulk: μ 

Density: ρ

Kinematic viscosity:  ν = μ / ρ