We propose a novel approach inspired by compressible fluids as a distributed and scalable solution to the deployment problem of mobile sensor networks in unknown environments. Our approach is based on fluid dynamics through which we model the sensor network as a fluid body and each sensor node as a fluid element. Originating from local neighborhood interactions, the principles of fluid flow are adapted to the deployment of the sensor network. Mimicking the diffusive and self-spreading behavior of compressible fluids in a mobile sensor network, we achieve the desirable properties of effective coverage, scalability, and distributed self-deployment. An adaptive deployment scheme is also devised for urban disaster environments where the number of nodes to be deployed may not be determined a priori. Simulation results show that our approach can guarantee a desired level coverability.