Subject: Stocks and Flows

Posted by Niall Palfreyman on 3/4/2004
In Reply To:Stocks and Flows Posted by Alfred Bosshard on 3/3/2004

Message:

I'm currently preparing an SD-based course on bioprocess engineering for the coming semester, and it's delivering me marvellous returns in terms of transfer between different disciplines: heat flow, electronics, fluid flow and chemical reaction all possess both "effort" and "flow"
variables. For example, V (voltage) is the effort variable which drives i (electric current) which accumulates as q (charge); here the effort variable is the second derivative, and the flow variable is the first derivative. Similarly, in mechanics, F (force) is the effort which accumulates as p (momentum), which together with m (mass) drives the flow v (velocity) which accumulates as x (position). I'm finding these analogies fascinating.

Niall Palfreyman.

Follow Ups:

Stocks and Flows - Bill Ellis 3/4/2004 
Stocks and Flows - Niall Palfreyman 3/6/2004