Vensim PLE- giving priority

[lgies]

Hi,

I'm new to dynamic modeling and am having a hard time conceptualizing how to approach the system I am trying to model.

Here is the situation:

I have a stock with a maximum value and one inflow. There are 4 outflows. 1 outflow is a constant rate (ie 30% of the total in the stock). The other 3 are variable based on how much is left in the stock. I'm not sure how to write an equation or use additional variables for the 3 stocks that will have variable rates. I want to be able to have the system run so that if the stock can't sustain the 3 remaining outflows, outflow 2 will receive more than outflow 3, and outflow 3 will receive more than outflow 4, etc.

I am using vensim PLE; any help would be appriciated!

[Administrator]

Is something like the attached what you need?

[lgies]

Yes, this is what I'm looking for. I still have a question though. I understand how the priority is given to the first outflow with a certain percentage. However, I have an additional 3 outflows that will be sharing different percentages of the remaining volume.

Is there a way to further allocate the flows based on priority between these 3 flows? Or would I have to give each a static precentage of the remaining volume (after the first outflow)?

Thanks.

[Administrator]

Is there a way to further allocate the flows based on priority between these 3 flows?

Yes, just replicate the structure I have put in. Or allocate based on a proportional demand basis.