Underwater ship-noise characterization

JRC, JAPAN

Introduction

Ship noise affects the underwater environment, requiring acoustic assessment. Since Japan has no large-scale underwater ranging capability, JRC Tokki invested in a portable sound-intensity system from Brüel & Kjær. This static ranging system uses hydrophones mounted on a floating raft to make underwater Noise Source Identification (NSI) measurements on large vessels.

Download case-study

chevron_left

Challenge
Solution
Resultado
Client Description

chevron_right

In order to get a complete characterization for the whole of the underwater structure of a ship, a portable system was needed that would enable field measurements. As the curvature of a ship’s stern and bow often varies, JRC Tokki needed a solution that could account for this by following the hull closely, at a uniform distance.

Underwater sound intensity measurements are made using phase-matched hydrophones mounted in a custom measurement jig suspended from a movable floating platform. Type 8104 Hydrophones are used at lower frequencies; the high frequency band is measured using the miniature Type 8103.

JRC Tokki can now create a complete characterization of the underwater structure using many individual measurements – a virtual “mesh” the covers the entire underwater surface of a ship. Using these measurements, contour maps can be made that give a 3D picture of the sound intensity performance of the ship’s hull.

JRC Tokki

JRC Tokki has become the first company in Japan with a large-scale underwater acoustic ranging capability thanks to a portable sound-intensity system using Brüel & Kjær equipment

Technology Used

Hidrófonos

Los hidrófonos HBK son transductores de sonido acuáticos calibrados individualmente. Tienen una respuesta de frecuencia plana y son omnidireccionales en un amplio rango de frecuencia. Todos nuestros hidrófonos tienen una célula de protección, son totalmente estancos, resistentes a la corrosión y soportan altos niveles de salinidad. Nuestros instrumentos son imbatibles en términos de profundidad, rango y precisión a la hora de medir sonido en el laboratorio o en estudios marinos de campo.

Leer más

Related Case Studies