On The Hydrodynamics Of A Skiff At Different Crew Positions

2013 ◽  
Author(s):  
Ignazio Maria Viola ◽  
Joshua Enlander
Keyword(s):  
Uncertainty Analysis ◽  
High Performance ◽  
Olympic Games ◽  
Towing Tank ◽  
Lower Resistance ◽  
Model Scale ◽  
Sailing Boat ◽  
Large Vessels

A set of towing tank tests was undertaken on a 1:4-model-scale high-performance small sailing boat, which was a candidate for the 2016 Olympic games. The resistance, sink and trim were measured and uncertainty analysis was completed. The boat was tested for different longitudinal positions of the crew in displacement, transition and fully planning regimes. The resistance measurements in the towing tank were well correlated with established empirical formulations developed for planning hulls. It was found that at low Froude numbers, forward crew positions allow lower resistance and resistance increases significantly for after crew positions, while at higher Froude numbers after positions allow lower resistance, and the resistance is less sensible to the crew position. These findings are in agreement with sailor experience and with measurements performed by other authors on large vessels.

Benchmark Study and Uncertainty Assessment of Planar Motion Mechanism Tests on KVLCC2 in a Circulating Water Channel

2021 ◽  
Author(s):  
Chengqian Ma ◽  
Ning Ma ◽  
Xiechong Gu
Keyword(s):  
Uncertainty Analysis ◽  
Water Channel ◽  
Planar Motion ◽  
Acquisition Time ◽  
Motion Mechanism ◽  
Towing Tank ◽  
Circulating Water ◽  
Benchmark Study ◽  
Hydrodynamic Derivatives ◽  
Planar Motion Mechanism

Abstract The benchmark experiment research for the maneuverability of a small-scaled ship model is critical for investigating the scaled effect on the maneuvering hydrodynamic derivatives, and validating the CFD technology. Till now, there is little research on the benchmark study and uncertainty analysis for the small-scaled ship which is frequently used in the Circulating Water Channel (CWC). Therefore, an experimental study of the planar motion mechanism (PMM) tests is performed in the CWC of the SJTU. The PMM tests performed in the CWC can avoid some disadvantages of those in the towing tank, such as the limitations on the acquisition time and frequency due to the size of the towing tank, interference of the carriage on the signal acquisition. In addition, the flow field visualization for the tests in the CWC is easier to achieve compared with the experiments in the towing tank, which helps the scholars to understand the characteristic of the wake field during maneuvers. The benchmark ship is the KVLCC2 with a scaled ratio of 1/128.77. The hull forces are recorded and processed to obtain the maneuvering hydrodynamic derivatives. To assess the quality of the acquired data, randomness analysis, stationarity analysis, normality analysis, and statistical convergence are performed for the PMM tests in the CWC for the first time. Finally, the uncertainty analysis (UA) method for the PMM tests performed in the CWC is also developed.

scholarly journals On the Calculation of Propulsive Characteristics of a Bulk-Carrier Moving in Head Seas

2020 ◽  
Vol 8 (10) ◽  
pp. 786
Author(s):  
S. Polyzos ◽  
G. Tzabiras
Keyword(s):  
Navier Stokes ◽  
Bulk Carrier ◽  
Time Step ◽  
Towing Tank ◽  
Model Scale ◽  
Time Period ◽  
Unsteady Rans ◽  
Computational Fluid Dynamics Cfd ◽  
The Time Domain ◽  
Propeller Performance

The present work describes a simplified Computational Fluid Dynamics (CFD) approach in order to calculate the propulsive performance of a ship moving at steady forward speed in head seas. The proposed method combines experimental data concerning the added resistance at model scale with full scale Reynolds Averages Navier–Stokes (RANS) computations, using an in-house solver. In order to simulate the propeller performance, the actuator disk concept is employed. The propeller thrust is calculated in the time domain, assuming that the total resistance of the ship is the sum of the still water resistance and the added component derived by the towing tank data. The unsteady RANS equations are solved until self-propulsion is achieved at a given time step. Then, the computed values of both the flow rate through the propeller and the thrust are stored and, after the end of the examined time period, they are processed for calculating the variation of Shaft Horsepower (SHP) and RPM of the ship’s engine. The method is applied for a bulk carrier which has been tested in model scale at the towing tank of the Laboratory for Ship and Marine Hydrodynamics (LSMH) of the National Technical University of Athens (NTUA).

Olympic competition climbing: the beginning of a new era—a narrative review

2020 ◽  
pp. bjsports-2020-102035
Author(s):  
Christoph Lutter ◽  
Thomas Tischer ◽  
Volker Rainer Schöffl
Keyword(s):  
High Performance ◽  
Olympic Games ◽  
Medical Knowledge ◽  
Maximum Speed ◽  
Prevention Measures ◽  
Injury Rates ◽  
New Era ◽  
Finger Injuries ◽  
Injury Frequency ◽  
Combined Mode

Climbing as a competition sport has become increasingly popular in recent years, particularly the sub-discipline of bouldering. The sport will debut in the Tokyo Summer Olympic Games. National and international competitions have three disciplines: lead (climbing with rope protection), bouldering (climbing at lower heights with mattress floor protection) and speed (maximum speed climbing on a standardised route in 1-on-1 mode). There is also a ‘combined mode’ of all three disciplines (combined) which forms the Olympic competition format; all competition formats are held on artificial walls. Existing literature describes a predominantly low injury frequency and severity in elite climbing. In comparison to climbing on real rock, artificial climbing walls have recently been associated with higher injury rates. Finger injuries such as tenosynovitis, pulley lesions and growth plate injuries are the most common injuries. As finger injuries are sport-specific, medical supervision of climbing athletes requires specific medical knowledge for diagnosis and treatment. There is so far little evidence on effective injury prevention measures in top athletes, and antidoping measures, in general, requiring further work in this field. An improved data situation regarding high-performance climbing athletes is crucial to ensure that the sport continues to be largely safe and injury-free and to prevent doping cases as extensively as possible.

Perceived Outcomes of a Biofeedback and Neurofeedback Training Intervention for Optimal Performance: Learning to Enhance Self-Awareness and Self-Regulation With Olympic Athletes

2016 ◽  
Vol 30 (4) ◽  
pp. 339-349 ◽  
Author(s):  
Margaret Dupee ◽  
Tanya Forneris ◽  
Penny Werthner
Keyword(s):  
High Performance ◽  
Olympic Games ◽  
Self Regulation ◽  
Personal Control ◽  
Training Intervention ◽  
Self Awareness ◽  
Semistructured Interview ◽  
Neurofeedback Training ◽  
Psychological States ◽  
Perceived Outcomes

The purpose of this study was to explore the perceived outcomes of a biofeedback and neurofeedback training intervention with high performance athletes. Five Olympic level athletes preparing for world championships and the 2012 Olympic Games took part in a 20 session intervention over the period of one year. At the completion of the intervention, a semistructured interview was conducted with each athlete. The athletes indicated that they became more self-aware, were better able to self-regulate both their physiological and psychological states, developed a greater sense of personal control, and a greater understanding of skills inherent in the field of sport psychology. Three of the athletes made the Canadian Olympic team for the 2012 Olympic Games and two of those athletes won bronze medals. The present study suggests that biofeedback and neurofeedback training may be useful in enabling athletes to perform optimally, in both training and competition, on a consistent basis.

scholarly journals Modern Athletes’ Preparation for the Olympic Games

Pedagogika ◽  
2015 ◽  
Vol 120 (4) ◽  
pp. 192-201
Author(s):  
Povilas Karoblis ◽  
Egidijus Balčiūnas ◽  
Einius Petkus ◽  
Robertas Tamulevičius
Keyword(s):  
High Performance ◽  
New Technologies ◽  
Olympic Games ◽  
Growth Stimulation ◽  
Technical Equipment ◽  
Training Methods ◽  
Training Process ◽  
Sport Training ◽  
Characteristics Analysis ◽  
The Olympic Games

Sport training process has its own problems related to different sport disciplines, thus, it is essential effectively to employ sport scientists’ and coaches’ initiatives as well as their researches and gained experience. The most important sport science function is to accept and share new technologies and good practices through sport training theory and didactics alongside to the new challenges for high performance sport that settle new requirements for coaches’ competency. Such tendencies are already reflected in present scientific studies and training modes of high performance athletes. Coaching more and more appears to come as many-angled process for athletes, who strive for elite level and must be prepared to stay at this level for many years ahead; and this involves not only coach’s specific, profession-related, and general competencies but also other parties-scientists, medics, managers-alongside to national support. When planning athletes’ training process for the Olympic Games, it is necessary to take into consideration the tendencies of sport and event perspectives as well as tendencies to anticipate results. The data of athlete’s main characteristics analysis, changes in sport training methods and its strategy, the development of increasing training loads, material facilities and technical equipment must be considered too. After analysing this, the training and participation in competitions of athletes and other participants has to be acquainted and summarized; then coach’s insights that are prognostic for sport results can be welcomed. Eventually, qualitative criteria for training evaluation must be settled, considering its scientific relevance, originality, influence to new scientific researches as well as scientists’ public behaviour, tolerance, and proper area-related growth stimulation.

scholarly journals THE RESISTANCE ASPECT OF FISHING BOAT SKIPJACK POLE AND LINE

2021 ◽  
Vol 4 ◽  
pp. 1-7
Author(s):  
Wolter R Hetharia ◽  
Eliza R De Fretes ◽  
Reico H Siahainenia
Keyword(s):  
Model Test ◽  
Ship Design ◽  
Full Scale ◽  
Suitable Method ◽  
Design Phase ◽  
Towing Tank ◽  
Model Scale ◽  
Fishing Boat ◽  
Fishing Vessels ◽  
The Difference

The operation of fishing vessels skipjack pole and line contributes in catching tuna and skipjack fishes particularly in Indonesian waters. A previous study conducted by the authors found that there was no suitable method provided for the resistance computation atearly ship design phase. Besides, there was aninitial trim existed on the vessel during the operation which contributes for the resistance. The purpose of the study is to find the difference of resistance between the model test and the existing methods. The study was executed also to find the effect of initial trim of the vessel. The study began with collecting the database of a parent ship then to develop and transform into a model-scale for testing purpose in the towing tank. The results of model test were converted to the full-scale vessel. The resistance of full-scale vessel was computed based on the Holtrop and Guldhammer methods. The result of full-of resistance obtained from the model test and the methods were collected, evaluated and compared. The results showed the difference of the resistance for all methods. The result of model test is greater 21 % than that of Holtrop method at the service speed of 10 knots. Meanwhile, the result of model test is lower 14 % than that of Gulhammer method at the same speed. In addition, at the speed of 10 knots the initial trim of 0.5O increase 5 % ofthe resistance, the initial trim of 1O increase 10 % of resistance and the initial trim of 2O increase 16 % of resistance compared to the vesselwithout initial trim. In conclusion, the existing resistance methods are not suitable to be applied for skipjack pole and line fishing vessels. In addition, the initial trim contributes to increase the resistance and should be avoided during the vessel operation.

scholarly journals Análisis histórico de la efectividad de los lanzamientos a portería de balonmano masculino (Historical analysis of throwing effectiveness in male handball)

Retos ◽  
2017 ◽  
pp. 228-232
Author(s):  
José Manuel Jiménez-Olmedo ◽  
José Julio Espina-Agullo ◽  
Carmen Manchado
Keyword(s):  
High Performance ◽  
Olympic Games ◽  
Historical Analysis ◽  
Video Recordings ◽  
El Alto

El objeto de este artículo es realizar un análisis de la efectividad de los lanzamientos en el alto rendimiento en balonmano. Para ello la muestra recoge 32 finales de Campeonatos del Mundo, de Europa y Juegos Olímpicos desde 1982 hasta 2012. El análisis de los lanzamientos se ha efectuado a partir de diferentes zonas, estableciendo como referencia la línea de 6 metros (centro y lateral), 7 metros y 9 metros (centro y lateral), e incluyendo los lanzamientos en situación de contraataque. El análisis de las videograbaciones se llevó a cabo con el software SportCode Pro v.8.5.2. La comparación de las frecuencias de las diferentes zonas de lanzamiento analizadas, se empleó la prueba Kruskal-Wallis. Los resultados demuestran las diferentes evoluciones de lanzamiento para cada una de las zonas analizadas. Se destaca el aumento de los lanzamientos de zona de 9 metros centro (9mC) (p=0,014) a lo largo de los periodos analizados. En cuanto a la evolución de goles, se destaca el aumento de los goles conseguidos en zona de 6 metros lateral, siendo mayor que en 6 metros centro (6mC). Finalmente se establece la evolución de la efectividad para cada una de las zonas analizadas, destacando el aumento de la efectividad para los lanzamientos de 7 metros (del 52,6% al 76,7%)  y contraataque (del 55,6% al 71,1%).Abstract. The aim of this paper is to analyze the throwing effectiveness in high performance handball. Therefore, the sample comprises 32 World Championships, European Championships and Olympic Games finals from 1982 to 2012. The analysis of throwing has been conducted from different areas, establishing as reference the line of 6 meters (center and lateral), 7 meters and 9 meters (center and lateral) , and including the throwing in counterattack situation. Video recordings were analyzed using SportCode Pro v.8.5.2 software and the Kruskal-Wallis test was used to compare the different throwing areas frequencies. As for the results, they show the different throwing evolutions for each of the analyzed area. It highlights the increase of 9 meters center throws (9mC) (p=0.014) during the analyzed periods. Concerning the number of goals, it is also emphasized that the goals scored from 6 meters lateral (6mL) were larger than from 6 meters center (6mC) Finally, it is set the evolution of effectiveness for each one of the analyzed areas, with an increase in effectiveness for the 7 meters throw (from 52.6% to 76.7%) and counterattack throwing (from 55.6% to 71.1%).

Sport Under Communism

2013 ◽  
Author(s):  
Robert Edelman ◽  
Anke Hilbrenner ◽  
Susan Brownell
Keyword(s):  
Cold War ◽  
Soviet Union ◽  
High Performance ◽  
Olympic Games ◽  
West Germany ◽  
Physical Culture ◽  
Competitive Sport ◽  
The Soviet Union ◽  
The Cold War ◽  
The Military

This article examines sport in the Soviet Union, East Germany, and China. Despite the early Soviet emphasis on mass physical culture, high-performance sport was the priority of these regimes and all three notionally used ‘amateurism’ to enhance national prestige. Having started out as opponents of Olympism, all three at different times came to prioritize winning medals at the Olympic Games. Despite similarities in the organization of sport—the state played a significant role and ties to the military and police were strong in all three countries—there were significant differences between them: China rejected competitive sport for much of the Mao era, whereas sport was one arena in which the GDR outshone West Germany. The article shows that during the Cold War sport was as much an arena of competition between socialist states as it was between the capitalist and communist worlds.

scholarly journals Is the game lost in advance? Being a high-performance coach and preserving family life

2019 ◽  
Vol 14 (4) ◽  
pp. 453-462 ◽  
Author(s):  
Hélène Joncheray ◽  
Fabrice Burlot ◽  
Mathilde Julla-Marcy
Keyword(s):  
Family Life ◽  
High Performance ◽  
Olympic Games ◽  
Sport Organizations ◽  
Structured Interviews ◽  
The Family ◽  
Sport Coaches ◽  
The Olympic Games

This article examines how high-performance sport coaches combine their professional and family lives. To address this issue, semi-structured interviews were conducted with 41 French coaches (8 females, 33 males) involved in the preparation of the French teams for the Olympic Games in Rio (2016), Pyeongchang (2018) and/or Tokyo (2020). The results show that all the coaches interviewed are engaged in a passionate relationship with their job. For some coaches, this commitment has an impact on their family life. Three groups of coaches stand out: (i) a majority of coaches who are unable to preserve their family life, (ii) coaches who maintain a distance from their profession and preserve their family life, (iii) coaches who have or have not preserved their family life and who position themselves as actors wishing to do everything possible to preserve the family life of the coaches they supervise. Thus, these results highlight, for some coaches, difficulties in combining professional and family life. For others, family life is a protection for engagement in a passionate profession. These data can provide useful information for sport organizations in charge of coaches.

Fair Play in the Perspective of Contemporary Sport

2011 ◽  
Vol 20 (5-6) ◽  
pp. 175-189 ◽  
Author(s):  
Aleš Sekot
Keyword(s):  
High Performance ◽  
Olympic Games ◽  
Fair Play ◽  
Young Generation ◽  
Recreational Sports ◽  
Equal Opportunities ◽  
Modern Times ◽  
Cultural Phenomenon ◽  
Olympic Movement ◽  
Value Modeling

Fair Play in the Perspective of Contemporary Sport Sport as a socio-cultural phenomenon of modern times is often portrayed as a renaissance of the Olympic ideals. Today, however, we can see that sports in many cases contributes to the emancipation process, particularly in developing countries, offers opportunities for strengthening national identity and fosters respect for state symbols. A wider context of applying the principle of fair play in sports has its indisputable philosophical and ethical dimensions. The first expresses the widening gap between high performance sports and recreational sports. The importance of schools in the value modeling of the principle of fair play in general and at the level of sports is given by the fact that their very nature is aimed at socialization and education. Olympic Movement must ensure that the Olympic Games preserve both the Olympic values and the principles of protecting the environment, respond to the needs of the young generation of athletes and enhance gender equality and equal opportunities.

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