Author Topic: Dymique flow quantity  (Read 5906 times)

Offline gimenomi

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Dymique flow quantity
« on: June 07, 2007, 13:31 »
Hello,

I would like to know, if it\'s possible to define an arrow with a dynamic way. I would like to define the flow quantity (arrow), inside my network, by a percent of a stock (place).

Thanks.

Offline pbeilschmidt

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Re: Dymique flow quantity
« Reply #1 on: June 11, 2007, 09:46 »
Hello,

yes, the modeling of dynamic flows in UMberto is possible. You can determine the flow quantity using a reference to a stock. For this purpose, you have to switch on the \"Dynamic Modeling\" flag in the Network Attributes / Calculation Method. The number of loops in this simple case is \"1\".

I have created a very simple example where an input of 20kg of Material1 arrives at a transition. The stock of another Material2 is checked in a storage place linked to the transition. If the quantity of the Material2 is above a certain value, then 25% of the stock is added to the incoming flow quantity.

The transition specification is defined with User Defined Functions as follows:
;if the quantity of stock is larger than 100
;then use 20% of the stock and add it
;if stock is below, don\'t add any stock
Y00=IF(>(R01,100),R01*0.20,0)+X00


I will send you the scenario file, so that you can check it in your Umberto. Please read more about this issue in chapter 9.3 of the Umberto User Manual
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Peter Müller-Beilschmidt
myUmberto Moderator
ifu Hamburg GmbH

Offline gimenomi

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Re: Dymique flow quantity
« Reply #2 on: June 11, 2007, 21:44 »
Hello,

thank you for your answer and for the example, it\'s very useful, but there is still something I don\'t understand. Can the reference stock value change during the calculation? In your example, how could I change the value of the reference stock (P3) if some material of the reference stock is use?

Offline pbeilschmidt

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Re: Dymique flow quantity
« Reply #3 on: June 18, 2007, 18:28 »
The change of stock is possible as well. I have sent two you two small examples.

The first is just one calculation, where 10% of the stock in P3 is taken and added to the flow. After calculation you will seen the reduced amount of Mat3 in the storage place, and the increased quantity in the other place.

The whole model gets more interesting, if you repeat this calculation 10 or 100 times. This is where you get the full idea of dynamic modeling. The second example shows 10 loops. After 10 loops the amount in P3 has reduced respectively (of course you can use absolute values rather than relative values). The calculation is shown as a dynamic modeling chart with three observed objects. You can edit the number of loops in the Network Attributes on the Calculation Method tab.
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Peter Müller-Beilschmidt
myUmberto Moderator
ifu Hamburg GmbH