{"id":396890,"date":"2024-12-10T07:34:07","date_gmt":"2024-12-10T07:34:07","guid":{"rendered":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/how-to-set-a-motion-in-a-specified-reference-frame\/"},"modified":"2024-12-10T07:34:07","modified_gmt":"2024-12-10T07:34:07","slug":"how-to-set-a-motion-in-a-specified-reference-frame","status":"publish","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/how-to-set-a-motion-in-a-specified-reference-frame\/","title":{"rendered":"How to set a motion in a specified reference frame"},"content":{"rendered":"<p>&lt;p class=&#8221;MsoNormal&#8221;&gt;Hello,&lt;\/p&gt;&lt;p class=&#8221;MsoNormal&#8221; style=&#8221;text-align: justify; text-justify: inter-ideograph;&#8221;&gt;&lt;span style=&#8221;mso-spacerun: yes;&#8221;&gt;&nbsp; &lt;\/span&gt;I am simulating a composite motion which consists of revolution and linear motion, details are shown in the following figures, as is shown in Figure 1 and 2, on one hand, the fluid 2 revolve around the Axis 1, on the other hand, the moving face which belongs to Fluid 2 move along the Axis 2, furthermore, there exits an angle&nbsp;<strong>&alpha;<\/strong>&nbsp;between axis 1 and axis 2, let&rsquo;s say 5&lt;span lang=&#8221;ZH-CN&#8221; style=&#8221;font-family: \u7b49\u7ebf; mso-ascii-font-family: Calibri; mso-ascii-theme-font: minor-latin; mso-fareast-theme-font: minor-fareast; mso-hansi-font-family: Calibri; mso-hansi-theme-font: minor-latin;&#8221;&gt;&deg;&lt;\/span&gt;(shown in Figure 3).&lt;\/p&gt;&lt;p class=&#8221;MsoNormal&#8221; style=&#8221;text-align: justify; text-justify: inter-ideograph;&#8221;&gt;&lt;span style=&#8221;mso-spacerun: yes;&#8221;&gt;&nbsp; &lt;\/span&gt;For revolution, I can use mesh motion or UDF(CG_MOTION) to realize it, but for linear motion, when I use the macro CG_MOTION, I need to decompose the linear velocity and then specify the velocity in x, y and z direction, it&rsquo;s very complicated.&lt;\/p&gt;&lt;p class=&#8221;MsoNormal&#8221; style=&#8221;text-align: justify; text-justify: inter-ideograph;&#8221;&gt;&lt;span style=&#8221;mso-spacerun: yes;&#8221;&gt;&nbsp; &lt;\/span&gt;As is shown in Figure 4, I created a reference frame which on the axis 2 and its y axis coincide with axis 2, then I only need to specify the velocity of y direction, but how to set the linear motion in the new reference frame? Or is there any other simple way to achieve this motion?&lt;\/p&gt;&lt;p class=&#8221;MsoNormal&#8221;&gt;Regards,&lt;span style=&#8221;mso-no-proof: yes;&#8221;&gt;&lt;!&#8211;[endif]&#8211;&gt;&lt;\/span&gt;&lt;\/p&gt;&lt;p class=&#8221;MsoNormal&#8221;&gt;<img decoding=\"async\" src=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2024\/12\/10-12-2024-1733815962-mceclip3.png\" \/>&lt;\/p&gt;&lt;p class=&#8221;MsoNormal&#8221;&gt;Figure 1&lt;\/p&gt;&lt;p class=&#8221;MsoNormal&#8221;&gt;&nbsp;&lt;\/p&gt;&lt;p class=&#8221;MsoNormal&#8221;&gt;&lt;span style=&#8221;mso-no-proof: yes;&#8221;&gt;<img decoding=\"async\" src=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2024\/12\/10-12-2024-1733815951-mceclip2.png\" \/>&lt;br&gt;&lt;!&#8211;[endif]&#8211;&gt;&lt;\/span&gt;&lt;\/p&gt;&lt;p class=&#8221;MsoNormal&#8221;&gt;Figure 2&lt;\/p&gt;&lt;p class=&#8221;MsoNormal&#8221;&gt;&lt;span style=&#8221;mso-no-proof: yes;&#8221;&gt;<img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2024\/12\/10-12-2024-1733815929-mceclip1.png\" width=\"696\" height=\"398\" \/>&lt;br&gt;&lt;!&#8211;[endif]&#8211;&gt;&lt;\/span&gt;&lt;\/p&gt;&lt;p class=&#8221;MsoNormal&#8221;&gt;Figure 3&lt;\/p&gt;&lt;p class=&#8221;MsoNormal&#8221;&gt;&nbsp;&lt;\/p&gt;&lt;p class=&#8221;MsoNormal&#8221;&gt;&lt;span style=&#8221;mso-no-proof: yes;&#8221;&gt;<img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/innovationspace.ansys.com\/forum\/wp-content\/uploads\/sites\/2\/2024\/12\/10-12-2024-1733815916-mceclip0.png\" width=\"647\" height=\"394\" \/>&lt;br&gt;&lt;!&#8211;[endif]&#8211;&gt;&lt;\/span&gt;&lt;\/p&gt;&lt;p class=&#8221;MsoNormal&#8221;&gt;Figure 4&lt;\/p&gt;&lt;p class=&#8221;MsoNormal&#8221;&gt;&nbsp;&lt;\/p&gt;&lt;p class=&#8221;MsoNormal&#8221;&gt;&nbsp;&lt;\/p&gt;<\/p>\n","protected":false},"template":"","class_list":["post-396890","topic","type-topic","status-publish","hentry","topic-tag-fluent-ansys-1","topic-tag-cg_motion-1","topic-tag-relative-motion-1","topic-tag-udf"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_forum_id":["27792"],"_bbp_topic_id":["396890"],"_bbp_subscription":["184661","199"],"_bbp_author_ip":["98.126.229.34"],"_bbp_last_reply_id":["397080"],"_bbp_last_active_id":["397080"],"_bbp_last_active_time":["2024-12-11 12:19:23"],"_bbp_reply_count":["2"],"_bbp_reply_count_hidden":["0"],"_bbp_voice_count":["2"],"_bbp_engagement":["184661","199"],"_btv_view_count":["457"],"_bbp_topic_status":["unanswered"],"_edit_lock":["1733816149:184661"]},"test":"excited"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/396890","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\/396890\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=396890"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}