[yek_irani]

Hi,


I am trying to set up an example where parcels are injected with a measured particle size distribution (PSD). I am trying to understand how to specify a size distribution based on the "type general" in the file reactingCloud1Properties.



One thread which often appears in searches related to my inquiry is:

https://www.cfd-online.com/Forums/openfoam-solving/117521-size-distribution-models-spray-modelling.html.


Another is this one:

https://www.cfd-online.com/Forums/openfoam-solving/200287-size-distribution-models-openfoam-4-x.html


Both links indicate that the required input needs to be a volume-weighted probability density function. Is there any link to official documentation which verifies that?


The format in which the size distribution is entered is to provide two columns. One column is an equidistant set of droplet sizes. I am having problems with column 2. The first link above indicates that it should be the volume probability for the corresponding droplet size (i.e. ΔQ3(xi)). However, when I look at tutorials/lagrangian/reactingParcelFoam/verticalChannel/constant/reactingCloud1Properties, I see the output below. The second column would have the hallmarks of ΔQ3(xi) if interpreted as a percentage. Now the thread I cite above is from 2013. I don't know about OpenFOAM's current status.



So, I want to understand if OpenFoam will take input for the second column as either as probability or percent probability, or whether it is now required to input as percent probability?


Thank you for your help.



sizeDistribution
{
type general;
generalDistribution
{
distribution
(
(10e-06 0.0025)
(15e-06 0.0528)
(20e-06 0.2795)
(25e-06 1.0918)
(30e-06 2.3988)
(35e-06 4.4227)
(40e-06 6.3888)
(45e-06 8.6721)
(50e-06 10.3153)
(55e-06 11.6259)
(60e-06 12.0030)
(65e-06 10.4175)
(70e-06 10.8427)
(75e-06 8.0016)
(80e-06 6.1333)
(85e-06 3.8827)
(90e-06 3.4688)
);
}
}

[oswald]

Two hints: Have a look at the source code, it's open And why not just try it out?


Afaik the first column is the diameter, with no special restrictions (like being equidistant) except that it should be in ascending order, and the second column is by default the frequency of occurrence of particles of this diameter, also without restrictions (regarding normalisation etc.). The second column can also be used as cumulative probability.

[yek_irani]

Lieber Oswald,

Many thanks for your response.

"Two hints: Have a look at the source code, it's open And why not just try it out?"

With that advice, there might be no need for this User Forum? Please bear in mind that a fair number of people who use this forum may either not be software programmers or they may have no experience with C++ and object-oriented languages.

But again, I emphasize I am grateful for your response.