Continuity Calculator

Introduction : This calculator calculates the change in air density as a function of time (the continuity equation) in one dimension (horizontal wind motion from west to east). The wind is moving through a box that has some length and an initial air density. In this calculator, you have five input values:
  1. wind speed (Uin, meters/second) coming in from the west
  2. wind speed (Uout, meters/second) exiting to the east
  3. length the wind travels (delta x, or dx) through the box
  4. initial density of the air (kg/m3) inside the box
  5. time the wind travels through the box (delta t, or dt)

What is being calculated is the change in air density over the period of time. High change values (like the 7.5 kg-m3-s-1 calculated at right using the default values) represent a significant change in air density.

The continuity equation is:

Mathematical equation for continuity equation

Continuity Calculator

Input Values:

Wind speed (Uin, meters/second) coming in from the west
Wind speed (Uout, meters/second) exiting to the east
Length of the box (m)
Initial density of the air (kg/m3)
Time in the box (seconds)

Results:

Change in density per unit time (kg-m3-s-1)