Waterjet Wake Characterization Suite

Bubble generation and entrainment in the transom region of a surface ship, along its hull, and in breaking waves are major ship signature contributors. For advanced ships such as the LCS, another source of air entrainment is added with the propulsion waterjets interacting with the free surface in the transom region. While significant research on breaking waves bubble generation exists, little is known about waterjet propulsion impact on bubbly wakes. Such wakes provide an excellent opportunity to wake homing torpedoes because of bubbles large acoustic cross section. Therefore, it is imperative to develop computational tools capable of predictive analysis for design optimization of bubbly wakes of waterjet driven ships. DYNAFLOW and ARL at the Pennsylvania State University propose to develop a suite of tools for modeling the waterjet driven ships bubbly wakes, conducting acoustic analysis relevant to wake homing threats, assessing threat performance in engagement simulations and conducting experiments to validate and refine the models. A suite of CFD codes known to reproduce conventional ship wakes properly will be used and modified by adding physical models of the waterjet free surface bubble entrainment mechanisms, which will be developed through experimental observation and modeling. BENEFITS: The proposed tool suite can be used for design evaluation of waterjet propelled surface ships. The developed models for bubble generation, propagation, and acoustics can be also combined with other CFD methods and could benefit commercial sectors such as fast ship industry, food manufacturing, oil and gas industry, chemical industry, etc.