{"id":34048,"date":"2019-03-19T12:16:37","date_gmt":"2019-03-19T12:16:37","guid":{"rendered":"\/forum\/forums\/topic\/udf-for-carreau-yasuda-viscosity-model\/"},"modified":"2019-03-19T12:16:37","modified_gmt":"2019-03-19T12:16:37","slug":"udf-for-carreau-yasuda-viscosity-model","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/udf-for-carreau-yasuda-viscosity-model\/","title":{"rendered":"UDF for Carreau-Yasuda Viscosity model"},"content":{"rendered":"<p>Hi All,<\/p>\n<p><\/p>\n<p>I am trying to write a UDF for the Carreau-Yasuda viscosity model according to the following equation.<\/p>\n<p><\/p>\n<p><img decoding=\"async\" src=\"https:\/\/us.v-cdn.net\/6032193\/uploads\/attachments\/256f4a4a-511c-490e-bc47-a9a500e004ba\/aa6beff7-b601-4fb5-98ff-aa1500c82201_yasua.jpg?width=690&amp;upscale=false\" alt=\"\"><\/p>\n<p><\/p>\n<p>Everything in the equation is a parameter which I can define apart from the shear rate term. I believe in fluent I can call this value using;<\/p>\n<p><\/p>\n<p>C_STRAIN_RATE_MAG(c,t), but when I try and raise this to a power as in the equation, I get an error saying &#8220;invalid binary expression, double ^ float), implying that the magnitude isn&#8217;t an integer? Any help is appreciated, and my UDF is below.<\/p>\n<p><\/p>\n<p>\/* Carreau-Yasuda Viscosity Model *\/<\/p>\n<p><\/p>\n<p>#include &#8220;udf.h&#8221;<\/p>\n<p><\/p>\n<p>float mu_inf=0.00345;<\/p>\n<p><\/p>\n<p>float mu_zero=0.16;<\/p>\n<p><\/p>\n<p>float lambda=8.2;<\/p>\n<p><\/p>\n<p>float p=0.64;<\/p>\n<p><\/p>\n<p>float n=0.2128;<\/p>\n<p><\/p>\n<p>DEFINE_PROPERTY(cell_viscosity,c,t)<\/p>\n<p><\/p>\n<p>{<\/p>\n<p><\/p>\n<p>real mu_lam;<\/p>\n<p><\/p>\n<p>real rate;<\/p>\n<p><\/p>\n<p>rate=(C_STRAIN_RATE_MAG(c,t));<\/p>\n<p><\/p>\n<p>mu_lam=mu_inf+((mu_zero-mu_inf)*(1+(lambda*rate)^(p)))^((n-1)\/p);<\/p>\n<p><\/p>\n<p>}<\/p>\n<p><\/p>\n<p>&nbsp;<\/p>\n","protected":false},"template":"","class_list":["post-34048","topic","type-topic","status-closed","hentry"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_old_topic_id":["6220"],"_bbp_old_topic_author_name_id":["Anonymous"],"_bbp_old_is_topic_anonymous_id":["false"],"_bbp_old_closed_status_id":["publish"],"_bbp_author_ip":[null],"_bbp_old_sticky_status_id":["normal"],"_bbp_likes_count":["0","0"],"_btv_view_count":["2773"],"_bbp_topic_status":["unanswered"],"_bbp_status":["publish"],"_bbp_topic_id":["34048"],"_bbp_forum_id":["27792"],"_bbp_engagement":["199","22555","160711","168876"],"_bbp_voice_count":["4"],"_bbp_reply_count":["3"],"_bbp_last_reply_id":["94988"],"_bbp_last_active_id":["94988"],"_bbp_last_active_time":["2019-09-27 10:53:20"]},"test":"beginermodel"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/34048","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics"}],"about":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/types\/topic"}],"version-history":[{"count":0,"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/34048\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=34048"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}