Pressure difference

Storyboard

When two columns of liquid with different heights are connected, it can generate a pressure difference that leads to a flow of liquid from the taller column to the shorter one. This movement continues until both columns reach the same height, eliminating any pressure difference.

>Model

ID:(1608, 0)



Mechanisms

Concept


ID:(15478, 0)



Connecting two liquid columns

Concept

If two columns of water with different heights at their bases are connected, a situation arises where there is a pressure difference along the connecting tube.

This setup allows us to study how the pressure difference generates a liquid flow along the tube. We can consider an element of liquid with a certain length and a section equal to that of the tube, and estimate the corresponding mass using the density. With the section, we can also convert the pressure difference into a force difference and, ultimately, study how volumes in liquids are accelerated due to pressure differences.

ID:(933, 0)



Pressure difference between columns

Concept

If there is the pressure difference ($\Delta p$) between two points, as determined by the equation:

$ dp = p - p_0 $



we can utilize the water column pressure ($p$), which is defined as:

$ p_t = p_0 + \rho_w g h $



This results in:

$\Delta p=p_2-p_1=p_0+\rho_wh_2g-p_0-\rho_wh_1g=\rho_w(h_2-h_1)g$



As the height difference ($\Delta h$) is:

$ \Delta h = h_2 - h_1 $



the pressure difference ($\Delta p$) can be expressed as:

$ \Delta p = \rho_w g \Delta h $

ID:(15704, 0)



Model

Concept


ID:(15479, 0)



Pressure difference

Description

When two columns of liquid with different heights are connected, it can generate a pressure difference that leads to a flow of liquid from the taller column to the shorter one. This movement continues until both columns reach the same height, eliminating any pressure difference.

Variables

Symbol
Text
Variable
Value
Units
Calculate
MKS Value
MKS Units
$\Delta h$
Dh
Height of liquid column
m
$h_1$
h_1
Height or depth 1
m
$h_2$
h_2
Height or depth 2
m
$\rho_w$
rho_w
Liquid density
kg/m^3
$p_1$
p_1
Pressure in column 1
Pa
$p_2$
p_2
Pressure in column 2
Pa
$\Delta p$
Dp
Variación de la Presión
Pa

Calculations


First, select the equation:   to ,  then, select the variable:   to 

Symbol
Equation
Solved
Translated

Calculations

Symbol
Equation
Solved
Translated

 Variable   Given   Calculate   Target :   Equation   To be used



Equations

As the the column force ($F$) generated by a column of liquid of the column height ($h$), the column Section ($S$), the liquid density ($\rho_w$), and the gravitational Acceleration ($g$) is

$ F = S h \rho_w g $



and the the water column pressure ($p$) is then defined as

$ p \equiv\displaystyle\frac{ F }{ S }$



we have that the the water column pressure ($p$) generated by a column of liquid is

$ p = \rho_w g h $

(ID 4249)

As the the column force ($F$) generated by a column of liquid of the column height ($h$), the column Section ($S$), the liquid density ($\rho_w$), and the gravitational Acceleration ($g$) is

$ F = S h \rho_w g $



and the the water column pressure ($p$) is then defined as

$ p \equiv\displaystyle\frac{ F }{ S }$



we have that the the water column pressure ($p$) generated by a column of liquid is

$ p = \rho_w g h $

(ID 4249)

If there is the pressure difference ($\Delta p$) between two points, as determined by the equation:

$ dp = p - p_0 $



we can utilize the water column pressure ($p$), which is defined as:

$ p_t = p_0 + \rho_w g h $



This results in:

$\Delta p=p_2-p_1=p_0+\rho_wh_2g-p_0-\rho_wh_1g=\rho_w(h_2-h_1)g$



As the height difference ($\Delta h$) is:

$ \Delta h = h_2 - h_1 $



the pressure difference ($\Delta p$) can be expressed as:

$ \Delta p = \rho_w g \Delta h $

(ID 4345)


Examples


(ID 15478)

If two columns of water with different heights at their bases are connected, a situation arises where there is a pressure difference along the connecting tube.

This setup allows us to study how the pressure difference generates a liquid flow along the tube. We can consider an element of liquid with a certain length and a section equal to that of the tube, and estimate the corresponding mass using the density. With the section, we can also convert the pressure difference into a force difference and, ultimately, study how volumes in liquids are accelerated due to pressure differences.

(ID 933)

If there is the pressure difference ($\Delta p$) between two points, as determined by the equation:

$ dp = p - p_0 $



we can utilize the water column pressure ($p$), which is defined as:

$ p_t = p_0 + \rho_w g h $



This results in:

$\Delta p=p_2-p_1=p_0+\rho_wh_2g-p_0-\rho_wh_1g=\rho_w(h_2-h_1)g$



As the height difference ($\Delta h$) is:

$ \Delta h = h_2 - h_1 $



the pressure difference ($\Delta p$) can be expressed as:

$ \Delta p = \rho_w g \Delta h $

(ID 15704)


(ID 15479)


ID:(1608, 0)