Realistic evaluation of hull performance for rowing shells, canoes, and kayaks in unsteady flow

In this study, we investigated the effect of hull dynamics in shallow water on the hydrodynamic performance of rowing shells as well as canoes and kayaks. An approach was developed to generate data in a towing tank using a test rig capable of reproducing realistic speed profiles. The impact of unsteady shallow-water effects on wave-making resistance was examined via experimental measurements on a benchmark hull. The data generated were used to explore the validity of a computational approach developed to predict unsteady shallow-water wave resistance. Comparison of measured and predicted results showed that the computational approach correctly predicted complex unsteady wave-resistance phenomena at low oscillation frequency and speed, but that total resistance was substantially under-predicted at moderate oscillation frequency and speed. It was postulated that this discrepancy arose from unsteady viscous effects. This was investigated via hot-film measurements for a full-scale single scull in unsteady flow in both towing-tank and field-trial conditions. Results suggested a strong link between acceleration and turbulence and demonstrated that the measured real-world viscous-flow behaviour could be successfully reproduced in the tank. Thus a suitable tank-test approach could provide a reliable guide to hull performance characterization in unsteady flow

HYDRODYNAMIC ANALYSIS OF ROWING HULL BASED ON THE FLOAT POSE

The rowing is one of the important events in the Olympic Games. In order to study the hydrodynamic performance of rowing, we finished the linetype mapping and the calculated the parameters of the double rowing model. Based on the resistance data of rowing at different states, we obtained the rule of resistance of rowing at different speeds. The study indicated that the enhancement of the physical force of the athletes seemed to be in proportion to the weight of the athletes and the results based on research shallow affected and optimized the design

Efficient Solving of Quantified Inequality Constraints over the Real Numbers

Let a quantified inequality constraint over the reals be a formula in the first-order predicate language over the structure of the real numbers, where the allowed predicate symbols are $\leq$ and $<$. Solving such constraints is an undecidable problem when allowing function symbols such $\sin$ or $\cos$. In the paper we give an algorithm that terminates with a solution for all, except for very special, pathological inputs. We ensure the practical efficiency of this algorithm by employing constraint programming techniques

Space station wardroom habitability and equipment study

Experimental designs in life-size mock-up form for the wardroom facility for the Space Station Habitability Module are explored and developed. In Phase 1, three preliminary concepts for the wardroom configuration are fabricated and evaluated. In Phase 2, the results of Phase 1 are combined with a specific range of program design requirements to provide the design criteria for the fabrication of an innovative medium-fidelity mock-up of a wardrobe configuration. The study also focuses on the design and preliminary prototyping of selected equipment items including crew exercise compartments, a meal/meeting table and a portable workstation. Design criteria and requirements are discussed and documented. Preliminary and final mock-ups and equipment prototypes are described and illustrated

A pilot study on the e-kayak system: A wireless DAQ suited for performance analysis in flatwater sprint kayaks

Nowadays, in modern elite sport, the identification of the best training strategies which are useful in obtaining improvements during competitions requires an accurate measure of the physiologic and biomechanical parameters that affect performance. The goal of this pilot study was to investigate the capabilities of the e-Kayak system, a multichannel digital acquisition system specifically tailored for flatwater sprint kayaking application. e-Kayak allows the synchronous measure of all the parameters involved in kayak propulsion, both dynamic (including forces acting on the paddle and footrest) and kinematic (including stroke frequency, displacement, velocity, acceleration, roll, yaw, and pitch of the boat). After a detailed description of the system, we investigate its capability in supporting coaches to evaluate the performance of elite athletes\u2019 trough-specific measurements. This approach allows for a better understanding of the paddler\u2019s motion and the relevant effects on kayak behavior. The system allows the coach to carry out a wide study of kayak propulsion highlighting, and, at the same time, the occurrences of specific technical flaws in the paddling technique. In order to evaluate the correctness of the measurement results acquired in this pilot study, these results were compared with others which are available in the literature and which were obtained from subjects with similar characteristics

Relationship of pre-competition arousal assessments to self-perceived performance competencies in rowers

This study used the technique of self-reporting to examine the relationship of pre-competition arousal symptoms and assessments to self-perceived performance competencies in rowers. A modified version of Rushall's (1977) Pre-Competition Psychological Checklist was employed allowing each subject to report pre-competition arousal symptoms, estimate of excitedness, estimate of winning, importance of event, and control over distractors. Post-race assessments of crew and individual performances were also noted. The research design selected was a number of replications of a single subject case study. The data were analyzed to determine 1) the existence of arousal patterns that were performance grade specific, 2) arousal (excitedness) - performance relationships, 3) estimation of winning - performance relationships, 4) importance of event - performance level relationship, 5) control over distractors - performance relationship, 6) arousal - estimation of winning relationships, 7) arousal - importance of event relationships, and 8) arousal - control over distractors relationship. All subjects exhibited grade specific arousal patterns. The arousal estimate and performance relationships were idiosycratic, however, when all subjects were considered together the relationship was positive and linear. Linear relationships were evidenced between 1) arousal and estimation of winning, 2) arousal and importance of event, and 3) arousal and control over distractors. The importance of event and control over distractors variable were related to performance in a more obvious manner than was arousal

Experimental analysis of paddling efficiency of elite and non-elite athletes with instrumented canoe sprint C1

Canoeing is an on-water sport admitted by the International Canoe Federation (ICF) and Canoe Sprint became an Olympic discipline in 1936: its programme includes events over 200 m, 500 m and 1000 m. There are numerous Canoe events in single (C1), double (C2) and four (C4) boats. In this discipline the canoeist is kneeling on one knee, and uses a single-bladed flat paddle. In the same way as kayaking, canoeing is a sport whereby propulsion of the boat is derived mainly from muscle actions of the upper body. Conversely, the kneeling position of the canoeist influences the dynamic behaviour of the hull and the force stroke exerted by the single-bladed paddle results in augmented ‘fluctuation’ of the average speed, in greater roll angle and wider pitch span of the canoe with respect to the kayak boat. Besides, the flat shape of the paddle determines the particular paddling technique. In canoeing high forces must be applied at high stroke rates and athletes are coached both in stroke technique and power or resistance training. Elite athletes stand out for the style and efficiency of the stroke, for power and resistance and for skills in the race strategy. Biomechanical measures of canoeing is an important asset to improve performance. In addition comparing results from test to test enables monitoring of an athlete's yearly, and year-to-year improvement. Finally, the experimental analysis of the main kinematical and dynamical parameters allows to examine the shape of the force curves for stroke error detection purposes and to reduce the ineffective hull movements. In this paper the performance and the paddling technique of two elite and two non-elite canoeists are presented by means of an on-water experimental apparatus. Moreover a comparison between the drive phase of the stroke in kayaking and canoeing is proposed. The goals of this research project were to (1) develop a system for on-the-water measurement of paddling performance in kayaking and canoeing, (2) demonstrate the potential of such a system to quantify efficiency and then (3) compare the main kinematical and dynamical parameters of single K1 and C1 boats and the technique differences in paddling style

The impact of cormorants (Phalacrocorax carbo carbo and Phalacrocorax carbo sinensis) on inland fisheries in the UK

Cormorants are piscivorous birds with a daily food intake (DFI) of approximately 500 g. They are a protected species under the Wildlife and Countryside Act 1981. In the UK, the number of over-wintering, inland cormorants increased steadily between 1970 and 1987, at a rate of between 5 and 10 % per annum. An increase of 74 % occurred between winter 1987/88 and 1990/91, and the population is still believed to be rising. The population growth was observed in all regions of the UK, on all habitat types. As cormorants exploited new habitats, ornithologists welcomed their increased presence. This contrasts with the views of angling bodies, who assert that the presence of cormorants, feeding daily on their fisheries, has a damaging impact on fish stocks with inevitable financial losses. Due to a lack of effective non-lethal control methods, the angling bodies wish to see the cormorants removed from the protected species list so their inland numbers can be controlled. Ornithologists insist that there is no scientific evidence proving cormorants are damaging to inland fisheries and so are opposed to any culling.A review of previous cormorant studies was undertaken to evaluate information on their ecology, feeding behaviour and predation impact. The general conclusion was no study had been able to prove cormorant predation damages fish populations, because few studies had moved beyond determining the mass of fish removed by the birds over the particular study period. No assessment had been made of the impact of that fish removal on the fish population dynamics and the angling performance of the fishery. This highlighted the requirement for research into the impact of cormorant predation on inland fisheries. This study was formulated to estimate cormorant predation impact on fisheries in a more realistic and robust manner than had previously been undertaken.The principal objective of the study was to integrate fish population and cormorant feeding dynamics data on specific fisheries (study sites) in such a way as to quantify, where possible, the full impacts of the cormorant predation. This required the following criteria at each study site:- evaluation of the historical status of fish and cormorant populations;- determination of the population and community dynamics of the fish stocks;- analysis of the angling effort and angling performance;- identification of the species, and estimation of the numbers and sizes of fish consumed and wounded by cormorants, and comparison with the numbers and sizes of the fish populations present;- determination of the occupancy on, and use by, cormorants at the selected sites.The work programme ran between September 1995 and July 1998, covering three winters of cormorant predation. At each study site, the cormorant feeding dynamics were assessed by detailed feeding observations and cormorant counts. This enabled data to be collected on the species, size and amount of fish being ingested during each foraging bout, and the diurnal and seasonal patterns of cormorant occupancy. As feeding observations were unable to completed at each site everyday, a modelling system was designed, using a Monte Carlo Simulation (MCS), to estimate the number and mass of fish being removed from the site over the whole winter period. The fisheries data were collected by electric fishing, seine netting, hydro-acoustics and angler catch analysis. The actual methods used at each site were dependent upon the physical conditions present. The data were analysed for fish population dynamics, including length frequency of species, year class strength, natural mortality rate and growth indices; and for angling performance, including catch per unit effort and the relative importance of species. Combining site-specific data for the fish species composition, and the length frequency distribution from fisheries surveys and the cormorants' diet, allowed preliminary predation impact assessment. Reconstruction of life tables from the fisheries data allowed integration of the cormorant feeding data from the Monte Carlo Simulation to assess impact in terms of the numbers of fish consumed on subsequent population densities. This enabled the status of the fish population at each study site to be shown, with and without cormorant predation over the three-year period, resulting in a detailed predation impact assessment.The fisheries studied were located in two regions of the UK, the Midlands and the North West of England. This enabled the research to be completed in two distinct geographical areas, with known and established over-wintering cormorant roosts. The Midland study sites were Holme Pierrepont Rowing Course, Colwick Park Trout Lake and the River Trent. The North West study sites were the lower River Ribble and Grimsargh number 3 Reservoir. These sites encompassed cyprinid and salmonid fish populations, and covered riverine and lacustrine fisheries