VIM Testing of a Paired Column Semi Submersible

2013 ◽  
Author(s):  
Jun Zou ◽  
Philip Poll ◽  
Dominique Roddier ◽  
Nathan Tom ◽  
Antoine Peiffer
Keyword(s):  
Hydrodynamic Interaction ◽  
Slenderness Ratio ◽  
Design Tool ◽  
Small Scale ◽  
Test Results ◽  
Towing Tank ◽  
Response Characteristics ◽  
Reliable Model ◽  
Physical Mechanics ◽  
Difficult Subject

This paper summarizes VIM towing test results of Houston Offshore Engineering’s Paired-Column Semisubmersible (PC Semi) platform that was performed at the UC Berkeley towing tank. The PC semi configuration is different from a conventional Deep Draft Semi (DD Semi) in three aspects, 1) 8 columns vs. 4 columns; 2) rectangle column vs. square column; 3) larger column slenderness ratio. Typically, a larger column slenderness ratio may result in more pronounced VIM. Since VIM significantly affects mooring and riser strength and fatigue, it is crucial to explore the VIM response characteristics of the PC Semi configuration. VIM has been characterized as a difficult subject with a complicated structural-hydrodynamic interaction. The physical mechanics is generally less well understood and numerical prediction is generally less reliable. Model testing has become an important and widely accepted design tool to derive reliable A/D envelops and drag coefficients. This project builds on the VIM testing experiences obtained in Finnigan and Roddier (2007), which showed that VIM testing at small scale is only slightly conservative. A scale factor of 1:160 was used in the present tests. The Reynolds Number for the tests varied from 15,000 to 30,000 depending on the towing speeds. This manuscript provides some details on the test setup and overall program, and highlights the key results of the tests.

scholarly journals Effect of water resistance on predictions of ship ice resistance using towing tests in ice basin

2021 ◽  
Vol 4 (398) ◽  
pp. 43-52
Author(s):  
Kirill Sazonov ◽  
◽  
Grigory Kanevsky ◽  
Mikhail Lobachev ◽  
◽  
...  
Keyword(s):  
Test Data ◽  
Model Test ◽  
Hydrodynamic Interaction ◽  
Water Resistance ◽  
Test Results ◽  
Improved Method ◽  
Towing Tank ◽  
Ice Floes ◽  
Ice Resistance

Object and purpose of research. The object under study is a method to determine ice resistance using towing tests of ship models. The purpose of the work is to develop a method that takes into account the water resistance effect on predictions of full-scale ship ice resistance. Materials and methods. The materials for development are model test data and earlier methods for determination of ice resistance on models, as well as recommendations of the International Towing Tank Conference (ITTC). Main results. The method is suggested to take into account the water resistance in analyzing the towing test data obtained in the ice basin, as well as the method for extrapolating the ice resistance due to hydrodynamic interaction of ice floes with underwater hull, including the scale effect. Conclusions. The methods that take into account the water resistance effect on predictions of ship ice resistance based on towing test data obtained in ice basins are reviewed and analyzed. An improved method to include the water resistance effect in a more correct way is suggested. For better comparison of test results in ice basin it is required to introduce a common method of including the water resistance effect using the method suggested in this work.

Structural Response Analysis of Tension Leg Platforms

1984 ◽  
Vol 106 (1) ◽  
pp. 10-17 ◽  
Author(s):  
K. Yoshida ◽  
M. Ozaki ◽  
N. Oka
Keyword(s):  
Equations Of Motion ◽  
Structural Response ◽  
Structural Member ◽  
Small Scale ◽  
Response Analysis ◽  
Test Results ◽  
Analysis Method ◽  
Regular Waves ◽  
Response Characteristics ◽  
Structural Responses

A linear response analysis method of the tension leg platform (TLP) subjected to regular waves is proposed. In this analysis method, flexibility of the superstructure can be taken into account in the equations of motion; response motions, tension variations of tendons and structural member forces are solved simultaneously. The applicability of this method is confirmed by comparison with the test results on two kinds of small-scale TLP models. The structural responses obtained from these calculations and their effects on tension variation of tendons are studied. Finally, several kinds of structural response characteristics are conclusively discussed.

UJI TARIK HIDRODINAMIKMODEL KAPAL BERSAYAP WiSE DENGAN LAMBUNG DASAR BERSTEP

2013 ◽  
Vol 12 (3) ◽  
Author(s):  
Iskendar Iskendar ◽  
Andi Jamaludin ◽  
Paulus Indiyono
Keyword(s):  
Comparative Study ◽  
Model Test ◽  
Hydrodynamic Model ◽  
Surface Effect ◽  
Center Of Gravity ◽  
Test Results ◽  
Flat Bottom ◽  
Towing Tank ◽  
Test Models ◽  
Wetted Surface Area

This paper describes hydrodynamic model tests of Wing in Surface Effect (WiSE) Craft. These craft  was fitted with  stephull  form in different location on longitudinal flat bottom (stepedhull planning craft) to determine the influences of sticking and porpoising motion performances. These motions are usually occured when the craft start to take-off from water surfaces. The test models with scale of 1 : 7 were comprised of 4 (four) stephull models and 1 (one) non-stephull model  as a comparative study. The hydrodynamic  tests were performed with craft speed of 16 – 32 knots (prototype values) in Towing Tank at UPT. Balai Pengkajian dan Penelitian Hidrodinamika (BPPH), BPPT, Surabaya. The resistance (drag) was measured by dynamo meter and the trim of model (draft changing at fore and aft  of model due to model speed) was measured by trim meter. By knowing the value of model trim, the wetted surface area can be determined. Then, the lift forces were calculated based on these measured values. The model test results were presented on tables and curves.  Test results show that models  with step located far away from center of gravity of the WiSE craft tend to porpoising and sticking condition, except if the step location on the below of these center of gravity. While model without step tends to sticking conditions.

Improved AEB algorithm combined with estimating the adhesion coefficient of road ahead and considering the performance of EHB

2021 ◽  
pp. 095440702110261
Author(s):  
Dequan Zeng ◽  
Zhuoping Yu ◽  
Lu Xiong ◽  
Junqiao Zhao ◽  
Peizhi Zhang ◽  
...  
Keyword(s):  
Joint Probability ◽  
Principal Component ◽  
Test Results ◽  
Safe Distance ◽  
Adhesion Coefficient ◽  
The Road ◽  
Response Characteristics ◽  
Emergency Braking ◽  
Multiple Beams ◽  
Maximum Method

This paper proposes an improved autonomous emergency braking (AEB) algorithm intended for intelligent vehicle. Featuring a combination with the estimation of road adhesion coefficient, the proposed approach takes into account the performance of electronic hydraulic brake. In order for the accurate yet fast estimate of road ahead adhesion coefficient, the expectation maximization framework is applied depending on the reflectivity of ground extracted by multiple beams lidar in four major steps, which are the rough extraction of ground points based on 3 σ criterion, the accurate extraction of ground points through principal component analysis (PCA), the main distribution characteristics of ground as extracted using the expectation maximum method (EM) and the estimation of road adhesion coefficient via joint probability. In order to describe the performance of EHB, the response characteristics, as well as the forward and adverse models of both braking pressure and acceleration are obtained. Then, with two typical roads including single homogeneous road and fragment pavement, the safe distance of improved AEB is modeled. To validate the algorithm developed in this paper, various tests have been conducted. According to the test results, the reflectivity of laser point cloud is effective in estimating the road adhesion coefficient. Moreover, considering the performance of EHB system, the improved AEB algorithm is deemed more consistent with the practicalities.

scholarly journals Illumination Normalization Algorithm Combination Analysis in Face Recognition

2017 ◽  
Vol 9 (3) ◽  
pp. 334-339
Author(s):  
Rokas Semėnas
Keyword(s):  
Face Recognition ◽  
Large Scale ◽  
Real Life ◽  
Direct Approach ◽  
Small Scale ◽  
Test Results ◽  
Illumination Normalization ◽  
Recognition Algorithms ◽  
Life Problems

Face recognition programs have many practical usages in various fields, such as security or entertainment. Existing recognition algorithms must deal with various real life problems – mainly with illumination. In practice, illumination normalization models are often used only for Small-scale futures extraction, ignoring Large-scale features. In this article, new and more direct approach to this problem is offered, used algorithms and test results are given.

scholarly journals The Development of Nervous Problem Based Modulewith Character Conservation for Nervous System Materials in the Senior High School

2018 ◽  
Vol 7 (3) ◽  
pp. 298-304
Author(s):  
Reefa Qudsiya ◽  
Lisdiana Lisdiana ◽  
Nugrahaningsih WH
Keyword(s):  
Nervous System ◽  
Product Design ◽  
Large Scale ◽  
Small Scale ◽  
Test Results ◽  
Research Subjects ◽  
Teaching Materials ◽  
Valid Test ◽  
Readability Test ◽  
Positive Results

Nervous system teaching materials available in schools do not contain scientific-related content as mandated by the 2013 curriculum. In addition, teaching materials also do not contain student character reinforcement content. The purpose of this study is to develop “Nervous Problem Based Module with a  Conservation Character” as a nervous system learning supplement. This type of research is Research and Development (R&D) using ten steps, namely identification of potential and problems, data collection, product design, product design validation, product design revisions, small scale trials, product revision I, large scale trials, product revision II, and final products. The research subjects were students of class XI of SMA N 1 Bae Kudus. Nervous Problem Based Module with a  Conservation Character  tested the feasibility, readability, and effectiveness. Feasibility tests obtained very valid results. Readability test results were very valid. Test effectiveness by applying  Nervous Problem Based Module with a  Conservation Character in learning, obtained effective results and can be used in learning. The insertion of the conservation character reinforcement in the module gives positive results on the character of students. It can be concluded that “Nervous Problem Based Module with a Conservation Character” is decent and effectively applied in the nervous system learning.

scholarly journals Pengembangan Rubrik Penskoran pada Asesmen Otentik untuk Materi Volume dan Luas Balok

2020 ◽  
Vol 4 (2) ◽  
pp. 275
Author(s):  
Yunita Rochmawati Jonan
Keyword(s):  
Authentic Assessment ◽  
Student Response ◽  
Small Scale ◽  
Development Research ◽  
Test Results ◽  
Assessment Of Learning ◽  
Teachers And Students ◽  
Scoring Rubric ◽  
Large Groups ◽  
Made In

ABSTRAK Tujuan penelitian pengembangan ini adalah menghasilkan sebuah rubrik penskoran pada asesmen otentikuntuk materi volume dan luas balok yang dapat digunakan oleh guru dan siswa. Rubrik ini dibuat sesuai dengan standar penilaian dalam kurikulum 2013. Penelitian pengembangan (R&D) ini menggunakan model Borg and Gall yang terdiri dari lima tahap yaitu penelitian dan pengumpulan data awal, perencanaan, pengembangan format produk, uji coba skala kecil, revisi akhir dan penyempurnaan produk. Hasil penelitian pengembangan ini berupa rubrik penyekoran holistik dan analitik dengan nilai sangat valid sebesar 94%. Analisis dari penelitian ini adalah angket kebutuhan bagi guru dan siswa sedangkan uji coba dilakukan melalui perorangan, kelompok kecil dan kelompok besar. Sedangkan kelayakan rubrik penskoran dari penilaian oleh ahli dengan menggunakan angket uji validitas materi, hasil belajar siswa, respon siswa serta tanggapan guru pengajar. Hasil penelitian ini menunjukkan bahwa rubrik penskoran ini efektif dalam membantu memperbaiki hasil ulangan dan cukup praktis serta dapat dipergunakan untuk memberikan penilaian hasil belajar yang sesuai dengan kurikulum 2013. Kata kunci: rubrik, penskoran, asesmen otentik.   ABSTRACT The purpose of this development research is to produce a scoring rubric on an authenticity assessment for the volume and area materials that can be used by teachers and students. The rubric is made in based on the assessment standards in the 2013 curriculum. This development research (R&D) uses the Borg and Gall model consisting of five stages of preliminary data research and collection, planning, product format development, small-scale trials, final revisions and product enhancements. The results of this development research include holistic and analytic scoring rubric with a very valid score of 94%. The rubric is analyzed fromquestionnaire for teachers and students, while trials are conducted through individuals, small groups and large groups. The feasibility of the scoring rubric from assessment by members by using the material validity test questionnaire, student learning results, student response and teacher responses. The results of this study show that the scoring rubric is effective in helping to improve the test results and is practical and can be used to provide assessment of learning outcomes in accordance with the 2013 curriculum. Keywords: rubric, scoring, authentic assessment.

scholarly journals Analysis and Modification of Methods for Calculating Axial Load Capacity of High-Strength Steel-Reinforced Concrete Composite Columns

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 6860
Author(s):  
Jun Wang ◽  
Yuxin Duan ◽  
Yifan Wang ◽  
Xinran Wang ◽  
Qi Liu
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
High Strength Steel ◽  
Slenderness Ratio ◽  
High Strength ◽  
Confinement Effect ◽  
Test Results ◽  
Composite Columns ◽  
Steel Reinforced Concrete ◽  
Modified Formula

To investigate the applicability of the methods for calculating the bearing capacity of high-strength steel-reinforced concrete (SRC) composite columns according to specifications and the effect of confinement of stirrups and steel on the bearing capacity of SRC columns. The axial compression tests were conducted on 10 high-strength SRC columns and 4 ordinary SRC columns. The influences of the steel strength grade, the steel ratio, the types of stirrups and slenderness ratio on the bearing capacity of such members were examined. The analysis results indicate that using high-strength steel and improving the steel ratio can significantly enhance the bearing capacity of the SRC columns. When the slenderness ratio increases dramatically, the bearing capacity of the SRC columns plummets. As the confinement effect of the stirrups on the concrete improves, the utilization ratio of the high-strength steel in the SRC columns increases. Furthermore, the results calculated by AISC360-19(U.S.), EN1994-1-1-2004 (Europe), and JGJ138-2016(China) are too conservative compared with test results. Finally, a modified formula for calculating the bearing capacity of the SRC columns is proposed based on the confinement effect of the stirrups and steel on concrete. The results calculated by the modified formula and the finite element modeling results based on the confinement effect agree well with the test results.

Development and Validation of a Design Tool for an Improved Pitot-Tube Jet-Pump Allowing Continuous Fluid-Fluid Separation

2021 ◽  
Author(s):  
Jan Deylen ◽  
Jessica Köpplin ◽  
Dominique Thevenin
Keyword(s):  
Oil Spills ◽  
Separation Efficiency ◽  
Scale Up ◽  
Design Tool ◽  
Pitot Tube ◽  
Polluted Water ◽  
Small Scale ◽  
Water Mixture ◽  
Jet Pump ◽  
Operation Conditions

Abstract A Pitot-tube Jet-Pump (PTJ pump) has been considerably modified and extended in order to continuously separate and transport liquids of different densities. As a first application, an oil-water mixture is considered in this work. The modified PTJ pump could be used as a primary separator for oil-polluted water (e.g., around off-shore platforms, after oil spills from ships), while additionally being able to transport the resulting fluid to further heaters, exchangers, centrifuges, distillation columns, etc., without necessitating additional machinery. The performance behavior of the separating PTJ pump (abbreviated SPP in what follows) has been first investigated with computational fluid dynamics (CFD), and then validated by comparison with experimental data acquired on a small-scale prototype. Based on these observations, a design tool has been developed to (i) predict performance and (ii) support proper device scaling. This tool is based on dimensionless parameters that are already employed for classical turbomachinery, similar to the Cordier chart. However, since the SPP works at an extremely low specific speed, its operating points lie outside the standard Cordier chart. To verify the accuracy of the design tool, a scale-up test has been conducted and validated by CFD, delivering a good agreement. A separation efficiency better than 99% has been obtained in the experiments for suitable operation conditions, while the numerical scale-up test reveals a head of 15.1 m and an oil content below 0.2% in the purified water at the High-Pressure Outlet.

Skin Friction Resistance of Ships

1957 ◽  
Vol 1 (03) ◽  
pp. 3-12
Author(s):  
F. H. Todd
Keyword(s):  
Skin Friction ◽  
Present Status ◽  
Comparative Studies ◽  
Scale Model ◽  
Small Scale ◽  
Model Data ◽  
Towing Tank ◽  
Friction Resistance ◽  
Small Scale Model

The International Towing Tank Conference (ITTC) is to hold its 8th meeting in Madrid in September of this year. One of the subjects to be discussed will be the perennial one of how to estimate the resistance of a ship from that measured on a small-scale model in a towing tank. The Skin Friction Committee of the Conference was charged at the last meeting in Scandinavia in 1954, with reviewing the available data and making recommendations to the Conference in Madrid which will, it is hoped, be universally acceptable. Such a decision would remove one of the principal difficulties experienced in the use of model data in comparative studies. It is believed that a review of the present status of our knowledge in this field may be of interest to the members of the Society at this time.

Sign in / Sign up

Export Citation Format

Share Document