scholarly journals Seakeeping Performance of a New Coastal Patrol Ship for the Croatian Navy

2020 ◽  
Vol 8 (7) ◽  
pp. 518
Author(s):  
Andrija Ljulj ◽  
Vedran Slapničar
Keyword(s):  
Full Scale ◽  
Coast Guard ◽  
Project Design ◽  
Test Results ◽  
Sea Trial ◽  
Seakeeping Performance ◽  
The World ◽  
Full Scale Tests ◽  
Marine Environmental ◽  
Scientific Purpose

This paper presents seakeeping test results for a coastal patrol ship (CPS) in the Croatian Navy (CN). The full-scale tests were conducted on a CPS prototype that was accepted by the CN. The seakeeping numerical prediction and model tests were done during preliminary project design. However, these results are not fully comparable with the prototype tests since the ship was lengthened in the last phases of the project. Key numerical calculations are presented. The CPS project aims to renew a part of the Croatian Coast Guard with five ships. After successful prototype acceptance trials, the Croatian Ministry of Defence (MoD) will continue building the first ship in the series in early 2020. Full-scale prototype seakeeping test results could be valuable in the design of similar CPS projects. The main aim of this paper is to publish parts of the sea trial results related to the seakeeping performance of the CPS. Coast guards around the world have numerous challenges related to peacetime tasks such as preventing human and drug trafficking, fighting terrorism, controlling immigration, and protecting the marine environmental. They must have reliable platforms with good seakeeping characteristics that are important for overall ship operations. The scientific purpose of this paper is to contribute to the design process of similar CPS projects in terms of the development of seakeeping requirements and their level of fulfillment on an actual ship.

Correlation Allowances in Model Tests Results: A Delicate Balance Between Performance, Accuracy and Commercial Interests?

2016 ◽  
Author(s):  
Gerco Hagesteijn ◽  
Patrick Hooijmans ◽  
Karola van der Meij
Keyword(s):  
Model Test ◽  
Performance Prediction ◽  
Model Tests ◽  
Full Scale ◽  
Test Results ◽  
Power Performance ◽  
Low Light ◽  
Sea Trial ◽  
Performance Accuracy ◽  
Full Scale Tests

Model tests at ballast and design draught are used to convert the sea trial results from the ballast trial draught to the contractual design draught. Correlation allowances in model test results and their effect on the trial performance prediction are of major importance. Nowadays it is not only typical to verify the contract speed but also the EEDI certification requires a verification of the speed power performance of the vessel. The use of a to favorable CA-value may lead to attractive performance figures, but also leads to higher fuel consumption figures than expected. Furthermore the design point of the propeller is affected, which leads to a too low light running margin and in some cases to erosive cavitation. During a study, large spreading in the values of the correlation allowances for design draughts have been found for merchant vessels tested at different model test institutes, but at ballast trial draught the spreading is much less. Can it happen that some institutes select favorable correlations allowances on the basis of inaccurate trial data of shipyards? Or should we accept a large spreading in correlation allowances and have these indeed been confirmed by sea trials at design draught? This paper will present a discussion using the experience of a large full scale trial database as well as the accuracy of model and full scale tests.

Automated design of high voltage pylons

2021 ◽  
Author(s):  
Jos de Bruijn ◽  
Sander van Alphen
Keyword(s):  
The Netherlands ◽  
Automated Design ◽  
Full Scale ◽  
Energy Resources ◽  
Power Lines ◽  
3D Fem ◽  
Steel Tubes ◽  
The World ◽  
New Energy ◽  
Full Scale Tests

<p>As new energy resources like solar, wind and hydropower are being used more and more over the world, the demand for transport of energy and with that the demand for powerlines is big. Also, in The Netherlands this is the case. TenneT (company responsible for the transport of energy in The Netherlands) had to realise a total of 75 km’s of power lines in one project called Wintrack II. This includes 41 different kind of pole types that carry the conductors. The conductors are carried by so called bipoles, these are conical steel tubes.‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌‌</p><p>To help TenneT a semi-automatic tooling was made to calculate and to model the different pole types. The poles are modelled with inventor and calculated with different software programs.</p><p>To validate the different calculations and used model’s 3D FEM-calculations are performed as well as full scale tests. Several kinds of calculations and designs are made, especially in steel and concrete. For example, calculations are made on vortex, prestressing of anchors, flange connections and next to that measurements are being performed on full scale poles.</p>

scholarly journals STUDY OF THE FIRE PERFORMANCE OF HYBRID STEEL-TIMBER CONNECTIONS WITH FULL-SCALE TESTS AND FINITE ELEMENT MODELLING

2016 ◽  
Author(s):  
Aaron O. Akotuah ◽  
Sabah G. Ali ◽  
Jeffrey Erochko ◽  
Xia Zhang ◽  
George V. Hadjisophocleous
Keyword(s):  
Finite Element ◽  
Load Ratio ◽  
Full Scale ◽  
Test Results ◽  
Structural Members ◽  
Fire Performance ◽  
Shear Connection ◽  
Timber Connections ◽  
Full Scale Tests ◽  
Connection Design

Connection design is critical in timber buildings since the connections tend to have lower strength than the structural members themselves and they tend to fail in a brittle manner. The effect of connection geometry on the fire performance of a hybrid steel-timber shear connection is investigated by full-scale testing. These tests were conducted by exposing the test specimens to the standard time-temperature curve defined by CAN/ULC-S101 (CAN/ULC-S101, 2007). Test results showed that the fire resistance of these connections depends on the load ratio, the type of connection and the relative exposure of the steel plate to fire. Finite element models of the connections under fire were constructed using ABAQUS/CAE and these were validated using the test results. These numerical model results correlate well with test results with ±8.32% variation.

scholarly journals A COMPARISON BETWEEN MODEL AND PROTOTYPE WAVES IN HARBOURS

1978 ◽  
Vol 1 (16) ◽  
pp. 38
Author(s):  
Sverre Bjordal ◽  
Alf Torum
Keyword(s):  
Physical Model ◽  
Model Test ◽  
Field Measurements ◽  
Full Scale ◽  
Common Method ◽  
Test Results ◽  
Open Coast ◽  
The World ◽  
Mooring Forces ◽  
Absolute Basis

A common method of estimating the sheltering effects of different breakwater locations and layouts is to carry out physical model wave disturbance tests. Such tests have been carried out in different laboratories throughout the world for many years. But to our knowledge no reports are available in the literature showing comparison between model measurements and field measurements. The trend is that we know more and more on the wave cl imate along our coasts. Hence we have a better basis to make our economical calculations on breakwaters. We therefore also want to operate our models on a more absolute basis rather than on a comparative basis. The trend in recent years has also been to study breakwater locations and layouts in order to minimize mooring forces and ship movements. On this background VHL found a comparison between model test results and field measurements necessary. Full scale measurements of waves were carried out in two harbours by VHL during the winter 1976/77. This paper will present the results of the comparison of the model and the full scale measurements in Berlevag and Vard0 fishing harbours on the open coast of Finnmark in the northern part of Norway (Fig. I) . The model tests, as well as the full scale measurements, have been sponsored by the Norwegian State Harbour Authorities.

Infrared Signature Suppression for Marine Gas Turbines: Comparison of Sea Trial and Model Test Results for the DRES Ball IRSS System

1994 ◽  
Vol 116 (1) ◽  
pp. 75-81 ◽  
Author(s):  
A. M. Birk ◽  
D. VanDam
Keyword(s):  
Model Test ◽  
Gas Turbines ◽  
Flow Model ◽  
Full Scale ◽  
Scale Model ◽  
Test Results ◽  
Sea Trial ◽  
Infrared Signature ◽  
Plume Temperature ◽  
Better Than

Sea Trials have recently been underway for Canada’s new City Class Patrol Frigate (CPF). These trials provided the first opportunity to measure the performance of the new DRES Ball Infrared Signature Suppression (IRSS) system installed on a ship. Prior to these trials 1/4-scale hot flow model test and computer simulation performance results were available. The CPF DRES Ball IRSS systems are installed on the exhaust uptakes of the GE LM2500 main gas turbines. The DRES Ball provides both metal surface cooling for all view angles and plume cooling. The DRES Ball significantly reduces the IR signature of the LM2500 exhaust. This paper presents a comparison between the 1/4-scale hot flow model test results with the full-scale sea trial results. Performance variables included in the comparison are: metal surface temperatures, back pressure, plume temperature distribution, and surface static pressures. Because of the confidential nature of the DRES Ball system performance, all classified data have been nondimensionalized so that only relative comparisons can be made between the full-scale and 1/4-scale data. The results show that the full-scale system performs better than the 1/4-scale model because of Reynolds number effects. The plume temperature, surface temperatures, and back pressure were all lower (better) than in the 1/4-scale model tests. One of the original concerns with the installation was that relative wind would degrade the performance of the DRES Ball onboard a ship. The wind effect was found to be benign during the trials.

scholarly journals Experience in conducting field tests of metal structural constructions of coatings of the “BrSTU”

2020 ◽  
Vol 212 ◽  
pp. 02015
Author(s):  
Mikalai Shalabyta ◽  
Andrei Shuryn ◽  
Tatsiana Shalabyta ◽  
Viacheslav Dragan
Keyword(s):  
Theoretical Calculations ◽  
Field Tests ◽  
Full Scale ◽  
Complex Structures ◽  
Building Structures ◽  
The World ◽  
Special Approach ◽  
Full Scale Tests ◽  
Degree Of Participation ◽  
First Time

There are quite often statically complex structures, the reliability of theoretical calculations of which needs experimental verification in the world practice of design and construction. Studies of building structures functioning can be full-scale or carried out on their models in laboratory conditions depending on the goals set. Full-scale tests of building structures are more expensive, therefore, their implementation requires a special approach and justification. However, to check the operation of complex, critical structures which primarily include metal spatial large-span structures of coatings of buildings and structures especially those used for the first time to assess their bearing capacity, to establish the degree of participation in the construction of each of the elements, to study the operation of individual new nodal elements etc., only full-scale tests are required.

“A sea of boats”

2021 ◽  
pp. 114-133
Author(s):  
Jessica DuLong
Keyword(s):  
New York ◽  
World Trade ◽  
World Trade Center ◽  
Full Scale ◽  
Coast Guard ◽  
Rescue Work ◽  
The World ◽  
Canal Street ◽  
Lower Manhattan ◽  
Trade Center

This chapter describes how, after both towers of the World Trade Center fell, Lower Manhattan had become an achromatic world churning with dust and paper. Desperate, ashy people pressed up against the railings along the water's edge. Though “a sea of boats” had already rallied — tugs, tenders, ferries, and more, pushing into slips and against the seawall to rescue as many as they could — more boats were needed. Now, just before 10:45 a.m., the Coast Guard formalized the rescue work already under way by officially calling for a full-scale evacuation of Lower Manhattan. At 11:02 a.m., the Coast Guard's evacuation calls were echoed by New York City's then mayor, Rudolph Giuliani. At this point, the mission grew exponentially. Now it was not only those caught in the immediate aftermath that needed transportation, but “everyone south of Canal Street.” In fact, workers were streaming out of buildings much farther north than Canal, all looking for a way home. While these people might not have been in immediate danger — though even that was unclear, given that the extent of the attacks was still unknown — they were still stranded, disoriented, and reeling.

scholarly journals Model-Scale/Full-Scale Correlation of NRC-OCRE’s Model Resistance, Propulsion and Maneuvering Test Results

2015 ◽  
Author(s):  
Michael Lau
Keyword(s):  
Test Data ◽  
Model Test ◽  
Model Tests ◽  
Full Scale ◽  
Test Results ◽  
Sea Trial ◽  
Model Scale ◽  
Performance Predictions ◽  
Ice Strength ◽  
Scale Data

There are a variety of model ices and test techniques adopted by model test facilities. Most often, the clients would ask: “How well can you predict the full scale performance from your model test results?” Model-scale/full-scale correlation becomes an important litmus test to validate a model test technique and its results. This paper summarizes the model-scale/full-scale correlation performed on model test data generated at the National Research Council - Ocean, Coastal, and River Engineering’s (NRC-OCRE) test facility in St. John’s. This correlation includes ship performance predictions, i.e., resistance, propulsion and maneuvering. Selected works from NRC-OCRE on the USCGC icebreaker Healy, the CCGS icebreaker Terry-Fox, the CCGS R-Class icebreakers Pierre Radisson and Sir John Franklin and the CCGS icebreaker Louis S. St. Laurent were reviewed and summarized. The model tests were conducted at NRC-OCRE’s ice tank with the correct density (CD) EGADS model ice. This correlation is based on the concept that a “correlation friction coefficient” (CFC) can be used to predict full-scale ship icebreaking resistance from model test data. The CFCs have been compared for correlation studies using good-quality full-scale information for the five icebreaker models in the NRC-OCRE’s model test database. The review has shown a good agreement between NRCOCRE’s model test predictions and full-scale measurements. The resistance and power correlation were performed for five sets of full-scale data. Although there is substantial uncertainty on ice thickness and ice strength within the full scale data sets that contributes to data scattering, the data suggest a conservative estimate can be obtained to address reasonably this uncertainty by increasing the model prediction by 15% that envelopes most data points. Limited correlation for maneuvering in ice was performed for the USCGC icebreaker Healy. Selected test conditions from the sea trials were duplicated for the maneuvering tests and turning diameters were measured from the arcs of partial circles made in the ice tank. Performance predictions were then compared to the full-scale data previously collected. Despite some discrepancy in ice strength and power level between the model tests and sea trial, the model data agree well with the sea trial data except for three outliers. Otherwise, the maneuvering data show a good correlation between the model test and sea trial results.

Sailing Performance of "Naniwa-maru" - A Full Scale Reconstruction of a Sailing Trader of Japanese Heritage

2001 ◽  
Author(s):  
Kensaku Nomoto ◽  
Yutaka Masuyama ◽  
Akira Sakurai
Keyword(s):  
Wind Speed ◽  
Wind Tunnel ◽  
19Th Century ◽  
Wind Velocity ◽  
Performance Prediction ◽  
Full Scale ◽  
Test Results ◽  
Sea Trial

"Naniwa-maru" is a reconstruction of a sailing trader that used to ply between Osaka and Edo, today's Tokyo, in the 18th to the mid-19th century. The rig was simple; single mast with a huge square sail. It was of totally wooden construction in a genuine Japanese manner. The present paper relates to her sailing sea-trial results compared with performance prediction based upon tank tests and wind tunnel studies. According to the trial the ship could reach as high as 70° to weather on her track and the speed then was some 30% of the true wind velocity in a fair sailing breeze. She was swiftest on a broad reach, achieving more than 40% of the wind speed. The said prediction proved to explain the test results fairly well.

The Role of Rubber Hysteresis in Skidding Resistance Measurements

1960 ◽  
Vol 33 (1) ◽  
pp. 151-157 ◽  
Author(s):  
C. G. Giles ◽  
Barbara E. Sabet
Keyword(s):  
Full Scale ◽  
Hysteresis Loss ◽  
Test Results ◽  
Friction Coefficients ◽  
Hysteresis Losses ◽  
Testing Techniques ◽  
Full Scale Tests ◽  
Tread Rubber ◽  
Natural And Synthetic

Abstract In this paper the authors have tried to give examples of some of the more important ways in which Dr. Tabor's paper on the importance of rubber hysteresis has contributed to a better understanding of the mechanism of friction between tire and road. It is evident that a number of the problems presented by past test results may now be explained in terms of rubber hysteresis losses, in particular, the mechanism of the dependence of skidding resistance on temperature, and the differences in performance between natural and synthetic tires. In relation to testing techniques it draws attention to the importance of temperature and to the need to standardize the hysteresis loss properties of test tires in addition to the hardness of tread-rubber. Finally, the most important of all, as Dr. Tabor suggests, his work opens up the possibility of improvements in tire characteristics, which could result in greatly increased friction coefficients and hence greater freedom from skidding under wet conditions. The limited full-scale tests the authors have been able to make seem fully to confirm this possibility.

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