Loading on a rigid target from close proximity underwater explosions

Article type: Research Article

Authors: Riley, Mark | Smith, Malcolm | van Aanhold, J.E. | Alin, Niklas

Affiliations: Defence Research and Development Canada – Atlantic, Dartmouth, NS, Canada | TNO Delft, Delft, The Netherlands | FOI Defence and Security Systems and Technology – Grindsjön, Grindsjön, Sweden

Note: [] Corresponding author. Tel.: +1 902 426 3100; ext, 358; Fax: +1 902 426 9654; E-mail: mark.riley@drdc-rddc.gc.ca

Abstract: The study describes recent simulation results for underwater explosions in close-proximity to rigid targets. Simulations are performed using Chinook, an Eulerian computational fluid dynamics (CFD) code. Predicted target loadings are compared with measurements taken from a series of experiments conducted under an international collaboration between Canada, The Netherlands, and Sweden. The simulations of the rigid target tests focused on the modelling of gas bubble collapse and water jetting behaviour. Both two-dimensional and three-dimensional simulations were performed. It was found that the two-dimensional analyses produced good bubble periods and reasonable impulse loading compared to experimental data. The time of arrival of the bubble collapse and water jetting were found to be very mesh dependent and refining the mesh did not always produce better results. The two-dimensional approach provides a good initial understanding of the problem for a reasonable computational effort. The three-dimensional simulations were found to produce improved impulse predictions. The numerical gas bubble radii time histories are also compared to empirical time histories.

Keywords: Underwater explosion, shock, gas bubble dynamics, water jetting, computational fluid dynamics, marine structures

DOI: 10.3233/SAV-2011-0650

Journal: Shock and Vibration, vol. 19, no. 4, pp. 555-571, 2012