Methods of construction of flow net
Flow net construction methods include Analytical methods, Electrical analogy method, Capillary flow model, Sand model and Graphical methods
What is flow net?
Flow net represents the flow of water through a soil graphically. In field, under sheet piles, under dams and under masonry structures flow is not 1D, it may be 2D/3D
What are the methods of construction of Flow net?
• Analytical methods
• Electrical analogy method
• Capillary flow model
• Sand model
• Graphical method
Analytical and Electrical Analogy methods
In analytical method - the solution of laplace equation is found out using the mathematical equations, it would be possible for simple problems.
Electrical analogy method
• It uses the similarity between the Darcy’s law and Ohm’s law
• Through the water medium salt is added and current is allowed to pass, based on the current flow pattern, flow net is constructed
Capillary flow model
Model of earth dam is placed between two glass plates and a head of water would be maintained on both sides.
• So water is allowed to flow and some dye is added to water and the path followed by the dye is observed.
• Based on that the flownet would be constructed
What are the methods of construction of Flow net?
A sheet pile is inserted between the upstream and downstream flow.
• The path followed by the water along the sheet pile creates a flow line.
• Impervious boundary creates another flow line.
• Bottom of the upstream and downstream water level would be two equipotential lines.
• Using these 4 boundary conditions a flownet would be constructed