Silent Ships - a New Challenge for the Shipbuilding Industry

This publication presents new research techniques for noise abatement on ships obtaining vibroacoustic parameters of passenger and crew accommodations for newly designed ships. The construction of low-noise ships is a new technical challenge for naval architects, shipbuilders and shipowners. It also requires a new way of looking at these problems. The suggested new research methods based on sound intensity (SI) and laser anemometry techniques (PIV, LDA) in combination with graphical presentation as acoustical imaging (AI) of the field distribution of acoustic wave flows, gives a full range of interpretation possibilities of energy effects and the precautions taken. This will ensure vibro-acoustic optimisation of the product and meet design and standardisation objectives for noise and vibration levels on board. SI analyses are supported by acoustic orthogonal decomposition (AOD) of disturbed acoustic vector fields with a turbulent structure. The innovative SI-AOD method, combined with acoustical imaging (AI) of the results, allows a comprehensive interpretation of noise causes and becomes an highly effective tool for noise abatement on board ships. With a new, holistic approach to explain the mechanism of penetration of structure-borne and airborne sounds into ship interiors, it creates a balance of acoustic power of local sources of noise, which is the basis for the choice of methods for noise reduction. The author describes the mechanism of noise generation inside shipboard accommodations and in shipboard HVAC systems.