# Pressure Gradient

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Pressure gradient, abbreviated as $$p_g$$, is the rate of change of pressure with respect to distance.  It is typically used to describe pressure variations within a fluid that is not in hydrostatic equilibrium.

The negative sign in the formula indicates that pressure decreases with increasing distance in the direction of gravitational acceleration.  The pressure gradient is a measure of the steepness of the pressure profile and is proportional to the density and gravitational acceleration of the fluid.  The formula is commonly used in fluid dynamics and atmospheric science to describe pressure variations in the atmosphere and oceans.  It is also used in geophysics to describe pressure variations within the Earth's crust and mantle.

### Pressure Gradient formula

$$dT\;/\;dx = -\; \rho \; g$$
Symbol English Metric
$$\frac{dT}{dx}$$ = pressure gradient $$psi\;/\;ft$$ $$Pa\;/\;m$$
$$\rho$$   (Greek symbol rho) = density of the fluid $$lbm\;/\;ft^3$$ $$kg\;/\;m^3$$
$$g$$ = gravitational acceleration  $$ft\;/\;sec^2$$ $$m\;/\;s^2$$

Tags: Pressure