{"id":457437,"date":"2026-04-30T06:04:43","date_gmt":"2026-04-30T06:04:43","guid":{"rendered":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/no-seepage-velocity-when-using-volume-ratio-dependent-permeability-curve\/"},"modified":"2026-05-02T02:52:01","modified_gmt":"2026-05-02T02:52:01","slug":"no-seepage-velocity-when-using-volume-ratio-dependent-permeability-curve","status":"answered","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/no-seepage-velocity-when-using-volume-ratio-dependent-permeability-curve\/","title":{"rendered":"No seepage velocity when using volume-ratio dependent permeability curve"},"content":{"rendered":"<p>&lt;p class=&#8221;ds-markdown-paragraph&#8221;&gt;Hello, everyone. I am using MAT63 to model water seepage in porous media with the *MAT_ADD_PERMEABILITY keyword. According to the manual, this permeability model can incorporate a permeability vs. volume ratio curve. However, when I use a volume ratio dependent curve (PMTYP=1), the simulation yields no seepage velocity, and the pore pressure distribution does not obey Darcy&#8217;s law. If I set a constant permeability (PMTYP=0), everything works fine.&lt;\/p&gt;&lt;p class=&#8221;ds-markdown-paragraph&#8221;&gt;Why might this happen? Is MAT63 not able to compute the volume ratio correctly, or am I misusing *ADD_PERMEABILITY?&lt;\/p&gt;&lt;p class=&#8221;ds-markdown-paragraph&#8221;&gt;Any insights or debugging advice would be greatly appreciated!<img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2026\/04\/30-04-2026-1777529005-mceclip1.png\" width=\"252\" height=\"135\" \/><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2026\/04\/30-04-2026-1777528988-mceclip0.png\" width=\"201\" height=\"133\" \/><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2026\/04\/30-04-2026-1777529021-mceclip2.png\" width=\"201\" height=\"133\" \/>&lt;\/p&gt;<\/p>\n","protected":false},"template":"","class_list":["post-457437","topic","type-topic","status-answered","hentry"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_forum_id":["27814"],"_bbp_topic_id":["457437"],"_bbp_subscription":["682044"],"_bbp_author_ip":["2408:8207:c05:5920:694e:d058:2d84:4fa2"],"_bbp_last_reply_id":["0"],"_bbp_last_active_id":["457437"],"_bbp_last_active_time":["2026-04-30 06:04:43"],"_bbp_reply_count":["0"],"_bbp_reply_count_hidden":["0"],"_bbp_voice_count":["1"],"_bbp_engagement":["682044"],"_btv_view_count":["89"],"_bbp_topic_status":["answered"],"_edit_lock":["1777688262:682044"]},"test":"1819614500qq-com"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/457437","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":1,"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/457437\/revisions"}],"predecessor-version":[{"id":457507,"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/457437\/revisions\/457507"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=457437"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}