how can I generate SIMO underwater acoustic channel
While the literature is small, the Oceans are large.  There is a large variation in physical detail.  Unlike RF, there are no ITU standard models. A serious effort really requires real data, You can spend 20 years refining a model.

You could start by looking at,


  Stojanovic, Milica, and James Preisig. "Underwater acoustic
  communication channels: Propagation models and statistical
  characterization." IEEE Communications Magazine 47.1 (2009): 84-89.


At 100Khz, a ray tracing model should be adequate and you can get ray models at Porter's Ocean Acoustic Library at:

http://oalib.hlsresearch.com/

Ray shooting can require a lot of trial and error to get eigenrays. At short ranges, an iso-velocity range independent model might be adequate.  Most models are Fortran, not Matlab, but you can call them from Matlab. If you look around the web, particularly those of Australian establishments , there is code with tighter MATALB integration.  Most prop code is deterministic.  Ira Dyer is a pioneer is random propagation, so papers that cite him, might be useful, and you can do that using Google Scholar. If you can read Russian, a lot of their literature is very good.

Noise models are local but at 100KHz, noise sources are going to be near.

Projector and forward volume scattering effects are hard to model. Without data, you need to make some guesses.