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Whitewater
Whitewater forms in a rapid context, in particular, when a river's gradient changes enough to generate so much turbulence that air is trapped within the water. This forms an unstable current that froths, making the water appear opaque and white. The term "whitewater" also has a broader meaning, applying to any river or creek that has a significant number of rapids. The term is also used as an adjective describing boating on such rivers, such as whitewater canoeing or whitewater kayaking. Fast rivers Four factors, separately or in combination, can create rapids: gradient, constriction, obstruction, and flow rate. Gradient, constriction, and obstruction are streambed topography factors and are relatively consistent. Flow rate is dependent upon both seasonal variation in precipitation and snowmelt and upon release rates of upstream dams. Streambed topography Streambed topography is the primary factor in creating rapids, and is generally consistent over time. Increase ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Whitewater
Whitewater forms in a rapid context, in particular, when a river's gradient changes enough to generate so much turbulence that air is trapped within the water. This forms an unstable current that froths, making the water appear opaque and white. The term "whitewater" also has a broader meaning, applying to any river or creek that has a significant number of rapids. The term is also used as an adjective describing boating on such rivers, such as whitewater canoeing or whitewater kayaking. Fast rivers Four factors, separately or in combination, can create rapids: gradient, constriction, obstruction, and flow rate. Gradient, constriction, and obstruction are streambed topography factors and are relatively consistent. Flow rate is dependent upon both seasonal variation in precipitation and snowmelt and upon release rates of upstream dams. Streambed topography Streambed topography is the primary factor in creating rapids, and is generally consistent over time. Increase ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Whitewater
Whitewater forms in a rapid context, in particular, when a river's gradient changes enough to generate so much turbulence that air is trapped within the water. This forms an unstable current that froths, making the water appear opaque and white. The term "whitewater" also has a broader meaning, applying to any river or creek that has a significant number of rapids. The term is also used as an adjective describing boating on such rivers, such as whitewater canoeing or whitewater kayaking. Fast rivers Four factors, separately or in combination, can create rapids: gradient, constriction, obstruction, and flow rate. Gradient, constriction, and obstruction are streambed topography factors and are relatively consistent. Flow rate is dependent upon both seasonal variation in precipitation and snowmelt and upon release rates of upstream dams. Streambed topography Streambed topography is the primary factor in creating rapids, and is generally consistent over time. Increase ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kayaks
A kayak is a small, narrow watercraft which is typically propelled by means of a double-bladed paddle. The word kayak originates from the Greenlandic word '' qajaq'' (). The traditional kayak has a covered deck and one or more cockpits, each seating one paddler. The cockpit is sometimes covered by a spray deck that prevents the entry of water from waves or spray, differentiating the craft from a canoe. The spray deck makes it possible for suitably skilled kayakers to roll the kayak: that is, to capsize and right it without it filling with water or ejecting the paddler. ] Some modern boats vary considerably from a traditional design but still claim the title "kayak", for instance in eliminating the cockpit by seating the paddler on top of the boat ("sit-on-top" kayaks); having inflated air chambers surrounding the boat; replacing the single hull with twin hulls; and replacing paddles with other human-powered propulsion methods, such as foot-powered rotational propellers and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Whitewater Kayaking
Whitewater kayaking is an adventure sport where a river is navigated in a decked kayak. Whitewater kayaking includes several styles. River running; where the paddler follows a river and paddles rapids as they travel. Creeking usually involving smaller, steeper, and more technical waterways. Creek boats tend to be short but high volume to allow for manoeuvrability while maintaining buoyancy. Slalom requires paddlers to navigate through "gates" (coloured poles hanging above the river). Slalom is the only whitewater event to be in the Olympics. Play boating involves staying on one feature of the river and is more artistic than the others. Squirt boating uses low-volume boats (usually made specifically for the paddler) to perform special moves in whitewater features. History Paddling on rivers, lakes and oceans is as old as the Stone Age. The raft, the catamaran, the canoe and the kayak evolved depending on the needs and environment of the indigenous peoples in different parts o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Whitewater Canoeing
Whitewater canoeing is the sport of paddling a canoe on a moving body of water, typically a whitewater river. Whitewater canoeing can range from simple, carefree gently moving water, to demanding, dangerous whitewater. River rapids are graded like ski runs according to the difficulty, danger or severity of the rapid. Whitewater grades (or classes) range from I or 1 (the easiest) to VI or 6 (the most difficult/dangerous). Grade/Class I can be described as slightly moving water with ripples. Grade/Class VI can be described as severe or almost unrunnable whitewater, such as Niagara Falls. Design The canoe (or just 'boat') used in casual whitewater canoeing is different from those used in whitewater racing. Traditionally, canoes were made of tree bark, sewn with tree roots and sealed with resin. Early whitewater boats were made of wood followed by aluminium and later fiberglass or kevlar, followed by more exotic composite materials including spectra, vectran and carbon fiber. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Youghiogheny River
The Youghiogheny River , or the Yough (pronounced Yok ) for short, is a U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map accessed August 15, 2011 tributary of the Monongahela River in the U.S. states of West Virginia, Maryland, and Pennsylvania. It drains an area on the west side of the Allegheny Mountains northward into Pennsylvania, providing a small watershed in extreme western Maryland into the tributaries of the Mississippi River. Youghiogheny is a Lenape word meaning "a stream flowing in a contrary direction". Variant names According to the Geographic Names Information System, it has also been known historically as: * Gawgawgamie, Ohio Gani River, Roonanetto, Yanghyanghgain, Yaughvaughani, Yauyougaine River, Yawyawganey, Yawyougaine River, Yeoyogani, Yochio Geni, Yoghioghenny River, Yogyogany River, Yohioganey, Yohogany, Youghiogeny River, Youghogania, Youghyaughye, Youghyoghgyina River, Yoxhio geni River, Yoxhiogany, Yo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Whitewater Racing
Wildwater canoeing is a competitive discipline of canoeing in which kayaks or canoes are used to negotiate a stretch of river speedily. It is also called "Whitewater racing" or "Downriver racing" to distinguish it from whitewater slalom racing and whitewater rodeo or Freestyle competition. General The objective of the sport is to go from the starting point of the course on a river to the end point as quickly as possible. Typical wildwater venues consist of Class II - IV whitewater, in contrast to extreme racing, which takes place on more difficult streams. Match competitions generally consist of a classic and a sprint race. A classic course is 4 to 6 miles (6–10 km) in length or 10 to 35 minutes in duration, while the Sprint is between 500 and 750 meters and lasts around 2 minutes. Although there is some specialization, the vast majority of racers compete in both classic and sprint. Competitors are placed in classes based on gender and boat type as follows: *K1 � ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rapid
Rapids are sections of a river where the river bed has a relatively steep gradient, causing an increase in water velocity and turbulence. Rapids are hydrological features between a ''run'' (a smoothly flowing part of a stream) and a ''cascade''. Rapids are characterized by the river becoming shallower with some rocks exposed above the flow surface. As flowing water splashes over and around the rocks, air bubbles become mixed in with it and portions of the surface acquire a white color, forming what is called "whitewater". Rapids occur where the bed material is highly resistant to the erosive power of the stream in comparison with the bed downstream of the rapids. Very young streams flowing across solid rock may be rapids for much of their length. Rapids cause water aeration of the stream or river, resulting in better water quality. Rapids are categorized in classes, generally running from I to VI. A Class 5 rapid may be categorized as Class 5.1-5.9. While Class I rapids are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Playboating
Canoe freestyle (also known as playboating) is a discipline of whitewater kayaking or canoeing where people perform various technical moves in one place (a playspot), as opposed to downriver whitewater canoeing or kayaking where the objective is to travel the length of a section of river (although whitewater paddlers will often stop and play en route). Specialised canoes or kayaks (boats) known as playboats are often used, but any boat can be used for playing. The moves and tricks are often similar to those performed by snowboarders, surfers or skaters, where the athlete completes spins, flips, turns, etc. With modern playboats it is possible to get the kayak and the paddler completely airborne while performing tricks. The competitive side of playboating is known as freestyle kayaking (formerly called rodeo). Playspots Playspots are typically stationary features on rivers, in particular standing waves (which may be breaking or partially breaking), hydraulic jumps, 'holes' and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eddy (fluid Dynamics)
In fluid dynamics, an eddy is the swirling of a fluid and the reverse current created when the fluid is in a turbulent flow regime. The moving fluid creates a space devoid of downstream-flowing fluid on the downstream side of the object. Fluid behind the obstacle flows into the void creating a swirl of fluid on each edge of the obstacle, followed by a short reverse flow of fluid behind the obstacle flowing upstream, toward the back of the obstacle. This phenomenon is naturally observed behind large emergent rocks in swift-flowing rivers. An eddy is a movement of fluid that deviates from the general flow of the fluid. An example for an eddy is a vortex which produces such deviation. However, there are other types of eddies that are not simple vortices. For example, a Rossby wave is an eddy which is an undulation that is a deviation from mean flow, but doesn't have the local closed streamlines of a vortex. Swirl and eddies in engineering The propensity of a fluid to swirl is use ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eddy (fluid Dynamics)
In fluid dynamics, an eddy is the swirling of a fluid and the reverse current created when the fluid is in a turbulent flow regime. The moving fluid creates a space devoid of downstream-flowing fluid on the downstream side of the object. Fluid behind the obstacle flows into the void creating a swirl of fluid on each edge of the obstacle, followed by a short reverse flow of fluid behind the obstacle flowing upstream, toward the back of the obstacle. This phenomenon is naturally observed behind large emergent rocks in swift-flowing rivers. An eddy is a movement of fluid that deviates from the general flow of the fluid. An example for an eddy is a vortex which produces such deviation. However, there are other types of eddies that are not simple vortices. For example, a Rossby wave is an eddy which is an undulation that is a deviation from mean flow, but doesn't have the local closed streamlines of a vortex. Swirl and eddies in engineering The propensity of a fluid to swirl is use ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Foam
Foams are materials formed by trapping pockets of gas in a liquid or solid. A bath sponge and the head on a glass of beer are examples of foams. In most foams, the volume of gas is large, with thin films of liquid or solid separating the regions of gas. Soap foams are also known as suds. Solid foams can be closed-cell or open-cell. In closed-cell foam, the gas forms discrete pockets, each completely surrounded by the solid material. In open-cell foam, gas pockets connect to each other. A bath sponge is an example of an open-cell foam: water easily flows through the entire structure, displacing the air. A sleeping mat is an example of a closed-cell foam: gas pockets are sealed from each other so the mat cannot soak up water. Foams are examples of dispersed media. In general, gas is present, so it divides into gas bubbles of different sizes (i.e., the material is polydisperse)—separated by liquid regions that may form films, thinner and thinner when the liquid phase ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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