{"id":159717,"date":"2021-06-22T13:04:21","date_gmt":"2021-06-22T13:04:21","guid":{"rendered":"\/forum\/forums\/topic\/acoustics-for-muffler\/"},"modified":"2021-07-19T13:11:43","modified_gmt":"2021-07-19T13:11:43","slug":"acoustics-for-muffler","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/acoustics-for-muffler\/","title":{"rendered":"Acoustics for muffler"},"content":{"rendered":"
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Hi,<\/p>\n

I am running an acoustics simulation on a muffler for a 3 cylinder engine in Micro-CHP. I am interested in the sound pressure level at the muffler outlet, especially for the low frequency range. Acoustics caused by the muffler itself is ignored as I am only interested in the noise created by the air flow. There is a big temperature difference between outlet and inlet as the muffler is connected to a heat exchanger. I am using mass flow inlet as that's the only known parameter to me. I am using realizable k-epsilon with enhanced wall, with incompressible ideal gas as fluid.<\/p>\n

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  1. Which acoustics model should I use? Since Ffowcs Williams and Hawkings doesn't work on noise propagation inside duct and wave equation require constant gas density, is Broadband a good\/only choice for me? Or the direct method suits me better?<\/li>\n
  2. For the inlet, must it be pulsating inlet? Can I use constant mass flow rate?<\/li>\n
  3. If it needs to be a pulsating inlet, which kind of wave for the exhaust gas from the engine should I use? Sine, Triangle, Pulse? I will define a time-dependant function either with Fluent Expression or with profile file, with the former ones seems more promising.<\/li>\n<\/ol>\n

    Thanks for the help. And feel free to point out any mistake that I made.<\/p>\n","protected":false},"template":"","class_list":["post-159717","topic","type-topic","status-closed","hentry"],"aioseo_notices":[],"acf":[],"custom_fields":[{"0":{"_bbp_author_ip":[""],"_bbp_old_reply_author_name_id":["Anonymous"],"_bbp_old_is_reply_anonymous_id":["false"],"_btv_view_count":["1570"],"_bbp_likes_count":["0"],"_bbp_topic_status":["unanswered"],"_bbp_status":["publish"],"_bbp_topic_id":["159717"],"_bbp_forum_id":["27792"],"_bbp_engagement":["13","187078"],"_bbp_voice_count":["2"],"_bbp_reply_count":["6"],"_bbp_last_reply_id":["182974"],"_bbp_last_active_id":["182974"],"_bbp_last_active_time":["2021-07-19 13:11:43"]},"test":"danielgkh"}],"_links":{"self":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/topics\/159717","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\/159717\/revisions"}],"wp:attachment":[{"href":"https:\/\/innovationspace.ansys.com\/forum\/wp-json\/wp\/v2\/media?parent=159717"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}