We will investigate Brownian motion in particle-fluid mixtures using computational fluid dynamics (CFD)-based numerical methods. The initial goal of the project is to validate that the CFD code can simulate Brownian motion at different particle-fluid density ratios for a single particle. The next step would be to extend the method to include multiple particles and a mixture of background fluids to see how Brownian motion influences migration and mixing phenomena in such mixtures. Mixture properties such as particle concentration, size, density, viscosity, etc. will be modified to see how they affect the particles and background fluids. We will be using an Immersed Boundary(IB) method implemented using IBUFlow software(written in Python) developed by Fraunhofer Chalmers Center.