Question

What is streamline? What are its properties?

Answer 1

A basic study on fluid dynamics is all required to answer the question. It is necessary to be clear about fluid flow (liquid and gas), types and properties in order to know about streamline flow and how it is different from other ways of fluid flow. Fluid dynamics is an important field to study effect and flow of any fluid and their effect in practical life

Complete step-by-step answer:
Streamline flow, also known as laminar flow, is a type of flow of liquid in which there is no sign of any vigorous movement of molecules. There is no turbulent change in velocity of these types of fluid. Though there can be a slight agitation in liquid but that too only at molecular level. Some of the major points that truly give us about streamline flow:

As the name depicts, laminar flow can be considered as a pile of lamina placed over each other. Similarly for fluids in streamline flow there are different layers of fluid flowing above each other at different velocity without interpreting the other layer’s property of flow.

Fluid in direct touch of the surface is in steady state while all layers above it will slide over each other with increasing velocity.

For streamline flow in a closed pipe system the middle layer flows with highest velocity while both upper and lower layers remain steady as they are in contact with the surface of the pipe.

In streamline flow different layers flow over each other without mixing in each other due to variation in velocity which adds to smoothness in flow.

Particles of streamline flow have steady flow with smooth and regular pattern.

In this flow there is no intersection of any layer within each other. A constant gap is maintained through the flow of fluid irrespective of direction change or velocity.

In this flow, at any point there is no change in pressure and velocity of flow in a specific layer. Different layers may have different velocity but molecules in a layer will always show constant velocity and pressure.

To change any streamline flow into turbulent flow velocity of fluid is to be increased above critical velocity of fluid. Critical velocity can be obtained from Reynolds Number.

Note: Streamline flow’s velocity vector can be achieved by drawing tangent to the path of flow. The direction of the tangent gives a velocity vector and also tells about direction of flow of fluid. To know the type of flow of fluid, it can be achieved by Reynolds No. of the fluid. Flow in liquid only occurs when fluid is under shear stress.