Viscosity is the property of a fluid that resists the relative motion of its adjacent layers. It is responsible for the internal friction within a fluid, which opposes the flow of the fluid.

Laminar flow is characterized by smooth, orderly, and predictable flow patterns. The fluid particles move in parallel layers, with no mixing or swirling. This type of flow occurs at low velocities and high viscosities.

Bernoulli's principle states that as the velocity of a fluid increases, the pressure exerted by the fluid decreases. The curved shape of an airplane wing causes the air to flow faster over the top of the wing than over the bottom, creating a pressure difference that generates lift.

The Reynolds number is a dimensionless number that compares the inertial forces to the viscous forces acting on a fluid. It is used to determine whether the flow is laminar or turbulent.

Surface tension is the property of a fluid that causes its surface to behave like a stretched elastic membrane. It is responsible for the formation of surface waves, as it resists the deformation of the fluid's surface.

Turbulent flow is characterized by chaotic and unpredictable flow patterns. The fluid particles move in random and irregular directions, creating mixing and swirling. This type of flow occurs at high velocities and low viscosities.

Drag is the force that opposes the motion of an object moving through a fluid. It is caused by the interaction between the fluid and the surface of the object.

The Froude number is a dimensionless number that compares the inertial forces to the gravitational forces acting on a fluid. It is used to determine whether the flow is subcritical or supercritical.

Compressibility is the property of a fluid that allows it to change its volume under pressure. It is responsible for the ability of a fluid to transmit pressure throughout its volume.

Helical flow is a type of fluid flow in which the fluid particles move in a helical or spiral pattern. This type of flow is often observed in fluids with high viscosity or in the presence of strong shear forces.

Buoyancy is the upward force exerted by a fluid on an object submerged in it. It is equal to the weight of the fluid displaced by the object.

The Elasticity number is a dimensionless number that compares the inertial forces to the elastic forces acting on a fluid. It is used to determine whether the flow is elastic or inelastic.

Fluidity is the property of a fluid that allows it to flow and deform easily. It is the opposite of viscosity.

Turbulent flow is characterized by chaotic and unpredictable flow patterns. The fluid particles move in random and irregular directions, creating mixing and swirling. This type of flow occurs at high velocities and low viscosities.