Dynaflow, Inc. conducts a full range of research, development, and consulting studies on bubble dynamics including analytical, numerical and experimental work. Often a combination of these techniques is used to solve a given problem. A wide range of numerical methods, including one-way and two-way bubble/flow interaction schemes, spherical and non-spherical bubble deformation models, boundary and vortex element methods, and Navier-Stokes simulations have been developed to study bubble dynamics in a broad range of flow conditions. Our experimental facilities including high speed photography are used in conjunction with the numerical models to study bubble dynamics as well as to validate the numerical simulations. Applications based on our fundamental research of bubble dynamics include: 


Interaction between two bubbles and a free surface
   

Underwater Explosions (UNDEX): The underwater detonation of an explosive produces a shock wave which propagates, leaving behind it a gas and vapor filled bubble cavity. The bubble cavity subsequently pulsates and migrates due to buoyancy or the presence of obstacles and may interact with a nearby structure and/or free surface. We are able to study the interaction between explosion bubble and nearby structure, and/or free surface numerically using boundary element based computer programs (2DynaFS©, 3DynaFS© and DFBEM© ) and experimentally with spark generated bubbles .

Vortex Cavitation Inception: Vortex cavitation inception occurs when small bubbles experience a sharp pressure reduction due to capture by the core of a strong vortex causing the bubbles to grow explosively. Such vortices can be generated by a propeller, for example. These bubbles collapse violently when they leave the low pressure region, producing sharp pulses of noise. We have developed software with a variety of bubble dynamics models to simulate bubble dynamics and interaction with the vortex flow field and to predict the acoustic noise.

Comparison of body displacement and bubble top and bottom tracking between 3DynaFS© results and experimental measurement points

Validation of 3DynaFS© simulation for bubble explosion under a floating cylinder case by comparing with spark generated tests
Multibubble and Cloud Cavitation: The behavior of multiple interacting bubbles and "clouds" of bubbles can vary substantially from that of single bubble dynamics.  We have conducted experiments, modeled multiple bubble dynamics effects and have developed numerical tools for modeling clouds of bubbles that include deformation, mass and heat transfer effects.
Interaction between multiple bubbles simulated by 3DynaFS©

Shallow water underwater explosion