DPM would be the main model, and I'd start here https://ansyshelp.ansys.com/account/Secured?returnurl=/Views/Secured/corp/v231/en/flu_udf/flu_udf_DPMDEFINE.html%23flu_udf_sec_define_dpm_body_force
Not sure about the electric field. The potential field may be sufficient, I'd avoid electrochemisty and MHD for now.
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