# 8 Types of Fluids Flow

The flows or flows of fluids are subject to certain terms and conditions, principles and laws of dynamics and the theory of turbulence.

Below are listed the main types of flows, which can be: laminar, turbulent, one-dimensional, two-dimensional, rotational, irrotational, permanent, variable, uniform, varied, free, forced, among others.

Laminar flow

It occurs when the particles of a fluid move along well-defined trajectories, presenting blades or layers (hence the name laminar) each preserving its characteristic in the middle. In laminar flow, viscosity acts on the fluid in order to dampen the tendency for turbulence to arise. This flow generally occurs at low speeds and in fluids that have high viscosity.

Turbulent flow

It occurs when the particles of a fluid do not move along well-defined trajectories, that is, the particles describe irregular trajectories, with random movement, producing a transfer of amount of movement between regions of liquid mass. This flow is common in water, whose viscosity is relatively low.

One-dimensional flow

Flow whose properties (velocity, density, pressure etc …), are exclusive functions of a single spatial and time coordinate, that is, they are represented as a function of average section values.

Two-dimensional flow

It occurs when the particles of a fluid flow in parallel planes and following identical trajectories, with no flow in the normal direction to the planes.

Rotational flow

It occurs when the particles of a fluid, in a certain region, rotate in relation to any axis. Rotational flow is also called vorticous.

Irrotational runoff

It occurs when the particles of a fluid, in a certain region, do not rotate in relation to any axis.

Permanent drainage

When the properties of a fluid at each point of it, do not vary over time.

Variable flow

Also known as non-permanent flow, it occurs when the properties of a fluid at each point of it, vary over time.

Uniform flow

A flow is considered uniform when all the cross sections of a given conduit are equal and the average speed, in all sections, at a given time, is the same. In other words, uniform flow is one in which the velocity vector has its characteristics (modulus, direction, direction) equal at all points in the fluid.

Varied flow

The one in which the velocity vector has characteristics (modulus, direction, direction), different in the points of the fluid.

Free flow

It occurs when all the cross sections of a liquid are in contact with the atmosphere. This situation occurs in rivers, streams and others. This flow will necessarily be due to the action of gravity. Also known as free surface flow.

Forced flow

It occurs inside pipes, occupying its entire geometrical area, with no contact with the external environment. The pressure that the liquid exerts in the pipeline is different from the atmospheric pressure. This flow is by gravitational action or by pumping.