Bubbles in the Ocean – The Good, the Bad and the Ugly

An anthology of the possibilities and challenges of multiphase flows in maritime technology.

After an introduction with a review of multiphase flow applications, ranging from your kitchen to shielding underwater noise with bubbly flows, the presentation will focus on cavitation in ship propulsion and drag reduction by air lubrication.

There is accumulating evidence of the relevance of nuclei concentrations in the seas that we navigate for cavitation dynamics and Underwater Radiated Noise (The Bad). Experiments have recently been conducted to understand the sensitivity of cavitation dynamics and URN for these nuclei concentrations. One set of experiments was measured on board the NIOZ owned MV Pelagia during a campaign in the Carribean Sea. Other experiments are currently being conducted in the brand new MultPhase Flow Tunnel of Delft University.

The governing mechanisms for Drag Reduction by Air lubrication (The Good) is still not entirely understood. Experimental campaigns in a.o. the MultiPhase Flow Tunnel were recently completed, including experiments in salt water. We will sketch the state of art on air lubrication and discuss some tentative conclusions on air lubrication in salt water when compared to fresh water.

Why bubbles are also Ugly will be explained in the presentation.

Speakers: Tom van Terwisga and colleagues

Program