Hydrodynamics and Fluid Flow
Expert-defined terms from the Undergraduate Certificate in Offshore Pipeline Engineering course at London School of Planning and Management. Free to read, free to share, paired with a globally recognised certification pathway.
Hydrodynamics and Fluid Flow Glossary #
Hydrodynamics and Fluid Flow Glossary
A #
A
Advection #
The process by which a fluid transports a property, such as heat or momentum, from one location to another. This occurs through the bulk motion of the fluid.
Archimedes' Principle #
A fundamental principle in fluid mechanics stating that the buoyant force on an object immersed in a fluid is equal to the weight of the fluid displaced by the object.
B #
B
Bernoulli's Equation #
An equation that describes the conservation of energy in a fluid flow system. It relates the pressure, velocity, and elevation of a fluid at any two points along a streamline.
Buoyancy #
The upward force exerted by a fluid on an object that is immersed in it. This force is equal to the weight of the fluid displaced by the object.
C #
C
Capillary Action #
The ability of a liquid to flow in narrow spaces without the assistance of, or even in opposition to, external forces like gravity.
Compressible Flow #
Flow in which the density of the fluid changes significantly due to changes in pressure and temperature. This type of flow is common in high-speed aerodynamics.
Continuity Equation #
An equation that expresses the principle of mass conservation for fluid flow. It states that the mass flow rate of a fluid is constant along a pipe or duct.
D #
D
Drag #
The force that opposes the motion of an object through a fluid. It is caused by the interaction between the object and the fluid.
Darcy's Law #
An equation that describes the flow of a fluid through a porous medium. It relates the flow rate to the pressure drop and the permeability of the medium.
E #
E
Eulerian Approach #
A method of describing fluid flow in which the properties of the fluid at a fixed point in space are studied over time.
F #
F
Fluid Dynamics #
The study of fluids in motion and the forces acting on them. It encompasses both hydrodynamics and aerodynamics.
Fluid Mechanics #
The branch of physics that deals with the behavior of fluids at rest or in motion. It includes the study of fluid properties, fluid flow, and fluid forces.
Fluid Viscosity #
A measure of a fluid's resistance to deformation or flow. It is a crucial property in determining the behavior of fluids in motion.
G #
G
Gravity Drainage #
A process by which a fluid flows under the influence of gravity. It is commonly used in the oil and gas industry to recover hydrocarbons from reservoirs.
H #
H
Head Loss #
The decrease in total energy of a fluid as it flows through a pipe or duct due to friction, bends, or other flow obstructions.
Hydraulic Jump #
A phenomenon in fluid dynamics where there is a rapid increase in the water depth and a decrease in the velocity of flow. It occurs when supercritical flow transitions to subcritical flow.
Hydrodynamics #
The study of the motion of fluids and the forces acting on them. It includes the analysis of fluid flow, turbulence, and drag forces.
I #
I
Incompressible Flow #
Flow in which the density of the fluid remains constant. This type of flow is commonly assumed in the study of fluid mechanics.
Irrotational Flow #
Flow in which the fluid particles do not rotate as they move. This type of flow is characterized by a velocity field that can be described by a scalar potential.
J #
J
Jet #
A narrow stream of fluid that is projected into a surrounding medium. Jets are commonly used in fluid mechanics experiments to study fluid behavior.
K #
K
Kinematic Viscosity #
A measure of a fluid's resistance to flow due to its internal friction. It is defined as the ratio of dynamic viscosity to density.
L #
L
Laminar Flow #
Flow in which the fluid moves in parallel layers with minimal mixing between them. This type of flow is characterized by smooth streamlines.
M #
M
Mass Flow Rate #
The amount of mass flowing through a cross-section of a pipe or duct per unit time. It is a fundamental quantity in the analysis of fluid flow.
N #
N
O #
O
Orifice #
An opening through which fluid flows. Orifices are commonly used in flow measurement devices and control valves.
P #
P
Poiseuille's Law #
An equation that describes the flow of a viscous fluid through a cylindrical pipe. It relates the volume flow rate to the pressure drop and the viscosity of the fluid.
Pressure Gradient #
The change in pressure per unit distance in a fluid flow. It is a driving force for fluid motion in pipes and channels.
Q #
Q
Quasi #
Steady Flow: A flow regime in which the flow properties change slowly with time. This approximation is often used to simplify the analysis of unsteady flows.
R #
R
Reynolds Number #
A dimensionless quantity that characterizes the flow regime of a fluid. It is the ratio of inertial forces to viscous forces in the flow.
S #
S
Stokes' Law #
An equation that describes the drag force on a small sphere moving through a viscous fluid at low Reynolds numbers. It is used to calculate the terminal velocity of the sphere.
Streamline #
A line that is everywhere tangent to the velocity vector of a fluid flow. Streamlines are useful for visualizing the flow direction and patterns.
T #
T
Turbulence #
Chaotic and irregular fluid motion characterized by eddies, vortices, and fluctuations in velocity. Turbulence is a complex phenomenon that is still not fully understood.
U #
U
Uniform Flow #
Flow in which the velocity of the fluid remains constant along streamlines. This type of flow is often used as an idealization in fluid mechanics.
V #
V
Velocity Profile #
A graph that shows how the velocity of a fluid varies across a cross-section of a pipe or channel. Velocity profiles are important for analyzing flow distribution.
Viscous Drag #
The drag force experienced by an object moving through a fluid due to the viscosity of the fluid. It is proportional to the velocity gradient near the surface of the object.
W #
W
Wake #
The region of disturbed flow downstream of an object moving through a fluid. Wakes are characterized by low pressure and high turbulence.
Water Hammer #
A surge in pressure that occurs in a fluid due to a sudden change in flow velocity. Water hammer can cause damage to pipes and valves if not properly controlled.
X #
X
X #
Component: The horizontal component of a vector quantity in a Cartesian coordinate system. In fluid mechanics, the x-component of velocity is used to describe flow in the horizontal direction.
Y #
Y
Yield Stress #
The minimum stress required to make a fluid flow. Fluids with yield stress behave like solids until a certain stress threshold is exceeded.
Z #
Z
Zero Velocity #
A special condition in fluid mechanics where the velocity of the fluid at a point is zero. This can occur at stagnation points or in regions of recirculating flow.