The activities of Ship Hydrodynamics represent the core of Brodarski Institut’s activities in maritime technologies, and are at the same time the first activities that were started with the establishment of Brodarski Institut more than seventy years ago.
They include model tests, development and optimisation of the hull forms and propulsors in the state-of-the-art laboratories (towing tank, cavitation tunnel), and propeller and ship model manufacturing shops.
The expertise includes designing of various types of vessels and propulsors, hydrodynamic testing and offshore engineering. Several proprietary ship hull form series form series for full ship, shallow draft full ships, semi-displacement boats and streamlined submerged bodies were developed within scientific projects in our laboratories.
Until today, more than 1450 ship models and more than 1200 propeller models have been manufactured and tested.
More then 30 percent of the tested models were fast ships including naval ships and special purpose ships designed for the needs of the police, coast guard and other authorities, or motor yachts.
Our expert knowledge and experience have helped us in establishing a wide network of clients among shipyards, design offices and propeller manufacturers in Croatia and abroad.
Large Towing Tank is used of model tests of surface ships, submarines and floating objects. Tank length enables large models to be tested and long measurement sygnals. These leads to highly accurate results.
Nowadays, resistance and propulsion tests are required as part of the set of model tests for determination of EEDI index.
Cavitation Tunnel is used for assessment of the propellers. Large Cavitation Tunnel has two working sections and is designed to test entire hull model with the propeller. In some cases, dummy model is manufactured as more appropriate related to the test requirements. Large working section is measuring 5.35m in length by 2.m width and 1.m in height.
Strong support to laboratory work is ensured by Measurement and Instrumentation Division, Ship Model Manufacturing Shop and Propeller Model Manufacturing Shop. Measurement and Instrumentation Division is responsible for day to day operation of towing tanks and carriages, operation of measurement equipment and data acquisition systems, maintenance of instrumentation and measurement equipment and operations and maintenance of computers and peripherals. Division is also involved in development, manufacturing and calibration of special equipment, instruments, transducers and automatic testing systems. Ship Model Manufacturing Shop is responsible for manufacturing of ship models and accuracy fabrication of other models for testing. Models are typically made from wood or when needed from fibreglass.
Ship Model Manufacturin Shop is equiped with 5 axis CNC milling machine.
Useful working field of CNC machine is:
- X axis 9000 mm
- Y axis 1700 mm
- Z axis 864 mm
The accuracy of CNC machine is 0,003 mm.
In propeller model manufacturing shop high precision propeller models, 2D and 3D hydrofoils, nozzles, rudders and appendages are manufactured as well as shafting systems for models.
Resistance and Propulsion:
- Evaluation of hull forms and preliminary predictions
- Optimization of hull forms on the basis of model tests
- Resistance tests
- Propulsion and Bollard Pull Tests
- Powering performance prediction analysis
- Podded Propulsor Tests
- 3D Wake measurements
- Streamlines tests (by means of paint and by means of tufts)
- Open water tests
Special expertise is gained in various types of optimization tests which require special systematical approach.
Consultancy at any stage of ship design
Seakeeping Tests in regular and irregular waves
Free Running Outdoor Manoeuvering Model Tests
Performance prediction, identification of problem areas related to ship motions (accelerations, slamming, speed loss, seasickness etc.)
Preliminary studies and optimization of launching
Launching tests of ship models and measurement of speed, accelerations, angles, vertical and horizontal trajectories, forces and bending moments during launch
Improvements in launching techniques to obtain required degree of ship’s stability safety and to minimize ship’s hull deformation during longitudinal or side launching
Propulsors and Cavitation:
Cavitation Induced Pressure Fluctuations
Model scale experiments of Cavitation Erosion
Evaluation of propeller designs and feasibility studies
High Speed Vehicles:
Resistance Test (carriage speed up to 14 m/s)
Dynamic Instability Tests
Full scale measurements
Full scale measurements were conducted for decades for all Croatian Shipyards enabling establishment of extensive and reliable database as basis for correlation procedures. Over 1500 ships were tested in full scale.
Speed and Power Trials
Propulsion testing – measuring mile, endurance test
Maneuvering testing according to IMO,USCG, ITTC etc.
Noise measurements, strength and vibration measurement, lighting measurement
In the area of ship design Brodarski Institute has prominent experience in design and development of naval ships and working and special purpose ships including submarines.
Consulting services for Ship Owners and Shipyards (supervision, specifications)
Hull form design and optimisation
Hydraulic Modelling and Measurements:
Experience in manufacturing and testing of hydraulic physical models for assessment of safety, environmental and economic considerations.
Harbours and coastal structures, wave loads, sedimentation
Mooring facilities, breakwaters
Hydro power plants and other structures
In this field, Brodarski institute is performing calibration of hydrometric instruments such as current meters. Towing tank dimensions (length of 276 m, width of 12.5 m and depth of 6 m) enable testing of up to 24 flow instruments simultaneously and carriage speed up to 14 m/s enables wide range of testing conditions. Carriage accomodates Clients and instrumentation.
VIBRATION, SHOCK AND STRENGTH
In our laboratory we offer mechanical resistance testing of devices and equipment to vibration, shock, bumps and hydrostatic pressure.
Mechanical mobility testing
Vibration equipment testing
Bumping equipment testing
Shock equipment testing
Hydrostatic pressure testing
Device designing for static and dynamic structure strenght testing
Strain gage measurements: static and dynamic
Elastic foundation expertise
Human vibrations expertise
Human shock expertise
Vibration, shock and stress numerical analysis