What is the meaning of hydraulic head?
Hydraulic head is one of the key parameters describing the mechanical energy state of a hydraulic system. It represents the mechanical energy per unit weight of the fluid in the system. Hydraulic head is defined as h = hp + hz, where h is the hydraulic head, hp is the pressure head, and hz is the elevation head.
What is hydraulic head in fluid mechanics?
Hydraulic head or piezometric head is a specific measurement of liquid pressure above a vertical datum. It is usually measured as a liquid surface elevation, expressed in units of length, at the entrance (or bottom) of a piezometer.
What is the head of a reservoir?
Head of a reservoir Since there is only an extremely low flow within the reservoir so no water level gradient, the head can be clearly seen: where the farthest watercourse discharges into the reservoir.
What are the components of hydraulic head?
The hydraulic head combines two components: (1) potential energy contained by the water by virtue of its elevation above a reference datum, typically mean sea level; and (2) additional energy contributed by pressure.
What is piezometric head formula?
Determining Piezometric Head in Groundwater Piezometric total head calculations in groundwater use the formula h=z+Ψ where h means total head or height of the groundwater level above the datum, usually sea level, while z represents the elevation head and Ψ represents the pressure head.
Why is hydraulic head important?
The hydraulic head is one of the most important metrics in hydrogeology as it underlies the interpretation of groundwater flow, the quantification of aquifer properties and the calibration of flow models. Heads are determined based on water-level measurements in wells and piezometers.
Can hydraulic head negative?
A downward flow component is indicated if the gradient is negative, meaning the hydraulic head is less at depth. Conversely, an upward flow component is indicated if the gradient is positive, meaning the hydraulic head is greater at depth.
What is datum head?
Datum head: It is the head possessed by fluid due to height above the datum. Unit: meter (m) ii. ii. Pressure head: It is the head possessed by fluid due to pressure force by the flowing fluid.
How do you calculate total head?
The total dynamic head of a water system must be considered when determining the size of pumping equipment to be installed. It determines the various head losses that the pump must overcome. Total dynamic head = elevation head + friction head loss + pressure head.
What is the formula of velocity head?
This term is commonly used in hydraulic engineering and represents the kinetic energy of a fluid flow within a given streamtube. If u is the velocity and g the acceleration due to gravity, the velocity head is defined by u2/2g. …
What is meant by total head?
The sum of the elevation head, pressure head, and velocity head of a liquid. For ground water, the velocity-head component is generally negligible.
What is total head of a pump?
Total Head: The height from the original water source up to the highest point to which the fluid will be pumped – the discharge point. Total Suction Head: The height between the fluid source (what is being pumped) and the pump itself.
How do you calculate the head of a centrifugal pump?
If the water level is 10 feet below the pump suction connection then the static head will be 10 + 15 = 25 feet. Therefore the total head will have to be at least 25 feet plus the friction head loss of the fluid moving through the pipes.
Is flow rate constant in a pipe?
The equation of continuity states that for an incompressible fluid flowing in a tube of varying cross-section, the mass flow rate is the same everywhere in the tube. Generally, the density stays constant and then it’s simply the flow rate (Av) that is constant.
What is flow rate equal to?
1: Flow rate is the volume of fluid per unit time flowing past a point through the area A. re the shaded cylinder of fluid flows past point P in a uniform pipe in time t. The volume of the cylinder is Ad and the average velocity is ¯v=d/t so that the flow rate is Q=Ad/t=A¯v.
Is flow rate directly proportional to pressure?
Flow rate Q is directly proportional to the pressure difference P2−P1, and inversely proportional to the length l of the tube and viscosity η of the fluid. Flow rate increases with r4, the fourth power of the radius.