14 research outputs found
Hydrodynamic impact loads in smooth water for a prismatic float having an angle of dead rise of 10 degrees
Impact-loads Investigation of Chine-immersed Models Having Concave-convex Transverse Shape and Straight or Curved Keel Lines
Climate Change, Coral Reef Ecosystems, and Management Options for Marine Protected Areas
Marine protected areas (MPAs) provide place-based management of marine ecosystems through various degrees and types of protective actions. Habitats such as coral reefs are especially susceptible to degradation resulting from climate change, as evidenced by mass bleaching events over the past two decades. Marine ecosystems are being altered by direct effects of climate change including ocean warming, ocean acidification, rising sea level, changing circulation patterns, increasing severity of storms, and changing freshwater influxes. As impacts of climate change strengthen they may exacerbate effects of existing stressors and require new or modified management approaches; MPA networks are generally accepted as an improvement over individual MPAs to address multiple threats to the marine environment. While MPA networks are considered a potentially effective management approach for conserving marine biodiversity, they should be established in conjunction with other management strategies, such as fisheries regulations and reductions of nutrients and other forms of land-based pollution. Information about interactions between climate change and more “traditional” stressors is limited. MPA managers are faced with high levels of uncertainty about likely outcomes of management actions because climate change impacts have strong interactions with existing stressors, such as land-based sources of pollution, overfishing and destructive fishing practices, invasive species, and diseases. Management options include ameliorating existing stressors, protecting potentially resilient areas, developing networks of MPAs, and integrating climate change into MPA planning, management, and evaluation
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NACA Technical Notes
Note presenting a prismatic float with an angle of dead rise of 10 degrees, which was subjected to smooth-water impacts in the impact basin. The investigation consisted of a series of impacts at fixed angles of trim of 3 degrees, 12 degrees, 20 degrees, and 30 degrees and at flight-path angles from 2 to 23 degrees. Results regarding the effect of dead-rise function and aspect-ratio factor on hydrodynamic load and chine immersion are provided
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NACA Technical Notes
Note presenting an investigation of hydrodynamic impact loads on chine-immersed bodies of heavy beam loading, which has been expanded to include transversely curved models in addition to models of prismatic shape. The paper presents the results from tests of a chine-immersed model with a circular-arc cross section with a radius of 1 beam. The data are presented in tables, and the coefficients of loads and motion are presented in figures as a function of trim and initial flightpath angles
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NACA Technical Notes
Note presenting a model with an inverted-V transverse shape and a dead-rise angle of -20 degrees as part of a study of hydrodynamic impact loads on chine-immersed bodies. A series of fixed-trim impacts of the inverted-V model were made in smooth water over a wide range of trim and initial flight-path angles at a beam-loading coefficient of 19.15 with a few impacts at beam-loading coefficients of 27.90 and 36.07. The data are presented in tables and in figures as variations of loads and motions (in coefficient form) with time, trim angle, and flight-path angle
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NACA Technical Notes
Note presenting a prismatic-float forebody with an angle of dead rise of 40 degrees that was subjected to smooth-water impacts in the impact basin. The tests were made at fixed trims of 3, 6, 9, and 12 degrees for a range of flightpath angles from approximate 2 to 22 degrees. The data are presented and converted into dimensionless variables for correlation of the experimental results with hydrodynamic impact theory and for comparison of the runs among themselves
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NACA Technical Notes
Note presenting an investigation of three narrow-beam models of concave-convex transverse shape and having, respectively, a straight keel, a curved bow, and a curved stern tested at the Langley impact basin as part of a larger study of hydrodynamic impact loads on chine-immersed bodies of heavy beam loading. Testing occurred over a wide range of trim and initial-flight-path angles. Results regarding the transverse curvature, longitudinal curvature, rough water, and observations on the constant-force-type bottom