Learning Forum

[Saeed]

Hello, 

I am trying to write a udf function for Rocky which particle size reduces over time based an equation. kco and Csat are the inputs of the model. if i add kco value 0.01 it works without any problem. But if i choose a very small value like 1e-14 for kco. all the parameters i wan calculate are either zero or without anychange and therfore there is no mass or volume change. I wrote the code based on the transient szie scale module which is one of the ready to use ones. 

Can you please help me with it ?

[Rob]

What does kco do in your model? Ie what is the impact of the value being so low?

[Saeed]

it is mass transfer rate constant. the low number is for most of materials in real world. 

[Rob]

And what does that do to any value that's calculated? A coefficient implies it's included in more maths.... 

[Saeed]

in line 159 of the code, kco is used to calculate the mass_change1 and mass_change is beeing for the rest of the parameters. 

[Rob]

And what sort of values are you getting for the other parameters? 

[Saeed]

for example, for mass_change1 in line 159 , i get 0 value. same as mass and volume increment. 

[Rob]

I meant the other values in that equation. If you're multiplying 1e-14 by "something" the product could be very very small if "something" is also a small number. 

[Saeed]

Thank you for your clarification. 

 i am multiplying by particle surface area and DEM time step. for example, in the first time step : 4pi*0.01*0.01*1e-14*1e-6 = 1.256637... e-23

which I get 0 for this value. 

[Rob]

There's a good chance the 10^-23 part is returning zero or is adding to something and that's returning the original value. 

[Saeed]

isnt double supposed to hold the value even that small ? 

Also, when I run the simulation a text file is generated called debug.log with the following line inside : [0109/120309.241:WARNING:resource_bundle_qt.cpp(116)] locale_file_path.empty() for locale 

can you please help me with them ?

[Rob]

It likely will, but potentially not everything you're using is double. 

 

[Saeed]

all parameters are double. 

I also noticed another issue. in line 155 , cdiss1=cdissolved1/group.volume. I have added cdiss1 and cdissolved1 as an output and realized that cdissolved1/cdiss1 is not the value of volume which was added as an input and mathematically is not working correctly. 

Do you have any suggestions about that ? I can copy and past the whole code here if it can help you.

Thanks

[Rob]

Which I will not be reviewing: we don't debug user code. The wider community are able to do that if they wish.