What are the characteristics of flow nets?
Properties of flow net are as follows: The angle of intersection between each flow line and an equipotential line must be 90o which means they should be orthogonal to each other. Two flow lines or two equipotential lines can never cross each other. quantity of seepage occurs in each flow channel.
What are the various methods for obtaining flow nets?
Various methods of obtaining flow nets are:
- Graphical method.
- Electrical flow Analogy method.
- Sand Model.
- Capillary flow Model.
- Solution of Laplace equation/Analytical method.
What is flow net and what are its application explain briefly?
A flow net is a graphical representation of two-dimensional steady-state groundwater flow through aquifers. Construction of a flow net is often used for solving groundwater flow problems where the geometry makes analytical solutions impractical.
What is boundary condition in flow net?
Flow nets are drawn based on the boundary conditions only. They are independent of the permeability of the soil and the head causing flow. The space formed between two flow lines and two equipotential lines is called a flow field. It should be in a square form.
What are the limitations of flow net?
The flow net analysis cannot be applied in the region closed to the boundary where the effects of viscosity are predominant. The flow net is not applied to sharply diverging flow , as the actual flow pattern is not represented by the flow net.
When constructing flow nets impermeable boundaries are?
since flow cannot cross impermeable boundaries, the flow at such a boundary must be parallel to it, i.e., impermeable boundaries are flow lines, and equipotentials must meet them at right angles. c. the water table is, by definition, the surface where P = 0; it can thus be an equipotential only if it is horizontal.
Why flow net is used?
To determine the amount of seepage and upward lift pressure below hydraulic structure. Once the flow net is constructed, the same one applies to flows at different discharges. A flow net analysis assists in the design of an efficient boundary shapes.
What type of boundary conditions are required for the flow net?
since flow cannot cross impermeable boundaries, the flow at such a boundary must be parallel to it, i.e., impermeable boundaries are flow lines, and equipotentials must meet them at right angles.
What are the boundary conditions for a flow net?
To construct a flow net we also need to identify the boundary conditions present for the flow. Boundary conditions are the restrictions that limit the flow in a certain space or area. A flow net is unique for a given set of boundary conditions.
What are the initial conditions for a boundary value problem?
For instance, for a second order differential equation the initial conditions are, With boundary value problems we will have a differential equation and we will specify the function and/or derivatives at different points, which we’ll call boundary values.
How do you find the boundary value of a differential equation?
For instance, for a second order differential equation the initial conditions are, y(t0) = y0 y′(t0) = y′ 0 y ( t 0) = y 0 y ′ ( t 0) = y 0 ′. With boundary value problems we will have a differential equation and we will specify the function and/or derivatives at different points, which we’ll call boundary values.
Are the flow nets valid for regions of a few meters?
The flow nets of Figures 5.2 and 5.3 are equally valid whether the regions of flow are considered to be a few meters square or thousands of meters square. The sketching of flow nets is something of an art.