Dear, I have been trying to obtain the band structure of water-stainless steel phononic crystal using Comsol 5.4 by using pressure acoustic, frequency domain (for water) and solid mechanics (for steel) with acoustic-structure boundary coupling both. But for some reason the band structure does not look right. The modes are too fluctuating and no bandgap. Please find the attached .mph file and let me know what I was doing wrong. Your support is greatly appreciated.
Thanks and Regards, Sabiju