# What is the difference between energy line and hydraulic grade line?

## What is the difference between energy line and hydraulic grade line?

A hydraulic grade line (HGL) can be drawn to show the variation of the piezometric head. An energy grade line (EGL) shows the variation of the total head. Since the difference between the total head and the piezometric head is the velocity head, the distance between the EGL and the HGL is also the velocity head.

## What is an energy grade line?

A line that represents the elevation of energy head (in feet or meters) of water flowing in a pipe, conduit, or channel. The line is drawn above the hydraulic grade line (gradient) a distance equal to the velocity head (V2/2g) of the water flowing at each section or point along the pipe or channel.

What does hydraulic grade line mean?

The surface or profile of water flowing in an open channel or a pipe flowing partially full. If a pipe is under pressure, the hydraulic grade line is that level water would rise to in a small, vertical tube connected to the pipe.

How do you calculate hydraulic grade line?

The Hydraulic Grade Line is a plot of the sum of two of the terms of the Bernoulli theorem: Fluid Head = The Flow energy + The Potential energy.

### How is EGL calculated?

The Starting EGL is simply the HGL + Velocity Head (V2/2g). This is where you break out your Continuity equation, Q = VA, and calculate V based on the cross-sectional area, A, of the flow in the pipe.

### What is hydraulic gradient line and total energy line?

Hydraulic gradient line (HGL) is the line joining the points representing the values of Piezometric head Presure head + elevation head at various cross-section of pipe in pipe flow. This line may go up or down in the flow direction. It will always lies below the total energy line in a pipe flow.

What do you mean by hydraulic gradient line and total energy line?

Hydraulic gradient line and total energy line are the graphical representation for the longitudinal variation in piezometric head and total head.

Can hydraulic grade line be below pipe?

1 illustrates the energy and hydraulic grade lines for open channel and pressure flow in pipes. As illustrated in Figure 1, if the HGL is above the inside top (crown) of the pipe, pressure flow conditions exist. Conversely, if the HGL is below the crown of the pipe, open channel flow conditions exist.

## What is total energy line?

Definition: Total Energy Line or Energy Grade Line i.e. TEL is defined as a line joining the points representing the total head. It means the total energy line represents the sum of (P/γ + V²/2g + Z). For ideal or non-viscous fluid there are no losses hence TEL for that fluid is a horizontal line.

## How do you calculate energy grade line?

The Energy Grade Line is a plot of the sum of the three terms of the Work-Energy equation or Bernoulli theorem: Fluid Head = The Kinetic energy + The Flow energy + The Potential energy.