{"id":403966,"date":"2025-01-07T17:04:45","date_gmt":"2025-01-07T17:04:45","guid":{"rendered":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/rocky-udf\/"},"modified":"2025-01-07T17:04:45","modified_gmt":"2025-01-07T17:04:45","slug":"rocky-udf","status":"publish","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/rocky-udf\/","title":{"rendered":"Rocky UDF"},"content":{"rendered":"<p>&lt;p&gt;Hello,&nbsp;&lt;\/p&gt;&lt;p&gt;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.&nbsp;&lt;\/p&gt;&lt;p&gt;Can you please help me with it ?&lt;\/p&gt;&lt;p&gt;<img decoding=\"async\" src=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2025\/01\/07-01-2025-1736269162-mceclip0.png\" \/>&lt;\/p&gt;<\/p>\n","protected":false},"template":"","class_list":["post-403966","topic","type-topic","status-publish","hentry","topic-tag-rocky-dem-1"],"aioseo_notices":[],"aioseo_head":"\n\t\t<!-- All in One SEO 4.9.10 - aioseo.com -->\n\t<meta name=\"description\" content=\"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\" \/>\n\t<meta name=\"robots\" content=\"max-image-preview:large\" \/>\n\t<link rel=\"canonical\" href=\"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/rocky-udf\/\" \/>\n\t<meta name=\"generator\" content=\"All in One SEO (AIOSEO) 4.9.10\" \/>\n\t\t<meta property=\"og:locale\" content=\"en_US\" \/>\n\t\t<meta property=\"og:site_name\" content=\"Ansys Learning Forum | Ansys Innovation Space\" \/>\n\t\t<meta property=\"og:type\" content=\"article\" \/>\n\t\t<meta property=\"og:title\" content=\"Rocky UDF | Ansys Learning Forum\" \/>\n\t\t<meta property=\"og:description\" content=\"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. 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