1.3.1. Linear superposition

In the preceding chapter it was explained under what conditions a pulse, formed by a zone of ΔP and I, is transmitted in one direction without changing its form.
In this chapter you will study the result of two wave pulses moving towards and across each other. To do so an important precondition has to be valid. It must be assured that all changes in pressure and current are small in comparison to those changes which are realistically possible in the system under study. If for instance a pipe can hold a pressure of 100 pressure units, we will study only cases with small changes of a few percent of this value.
Under those circumstances it can be assumed in a good approximation that two wave pulses together will add up linearly and that no further non-linear effects will occur. The same has to be valid for changes of current. Here too, we will assume only small values for I, so that two currents at the same place will add linearly.

1.3.2. Superposition of two pulses of equal seize

The following simulation shows two pulses of equal seize which move towards each other and which will overlap and separate again. To study the process in detail the step button should be used to activate the simulation.

Two pulses moving with opposite orientation

The simulation shows how these pulses move towards each other, then completely overlap and disconnect again.

Simulation of 2 pulses moving in opposite direction
(prepared simulation: 1-3-1-equal-pulses.xml)

It is advisable to compare this procedure with the situation that was presented in the section "1.2.5. A zone of increased pressure and its change in time."

1.3.3. Superposition of two pulses of different seize

In following simulation two wave pulses of different seize are given which move towards each other and will overlap and separate again.

Simulation of 2 pulses of different seize moving in opposite direction
(prepared simulation: 1-3-2-different pulses.xml)

It is advisable to compare this procedure with the situation described in the section "1.2.9. Pulse transmission for an arbitrary ratio of ΔP/I"

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