I have learnt to evaluate bandgaps for 2D and 3D phononic crystals using COMSOL. But is it possible to do the same for 1D Phononic Crystals in COMSOL?

I have tried to do (by 2D model) it using periodic continuity boundary conditions for infinite representation of cells and Periodic Floquent boundary conditions for infinite repetition of unit cell. I am getting the dispersion curves and also faintly able to compare it with other methods like Transfer matrix method. However, COMSOL gives too many curves in the graph, may be it is bcz COMSOL not particularly gives the dispersion curves for S wave or P wave (as the case we do it in transfer matrix) but for all possible random particle vibration. Please suggest me how to get it particularly for s wave or p wave. (Particle vibrations are not a matter of concern for 2D or 3D, as they are meant to deal with any possible vibration in 2D or 3D as the case may be).