Hydraulic structures

Source: Wikipedia. Pages: 61. Chapters: Breakwaters, Water turbines, Weirs, Pelton wheel, Dam, Water wheel, Cross-flow turbine, Tyson turbine, Marina del Rey, California, Port of Bridgetown, South Gare, Band-e Kaisar, Spillway, Gorlov helical turbine, Mundaring Weir, Boylston Street Fishweir, Shrouded tidal turbine, Kaplan turbine, Reverse overshot water-wheel, Fishing weir, Stepped spillway, Great South Wall, Francis turbine, Bull Wall, Plymouth Breakwater, Air entrainment, San Pedro Bay, Roller dam, Chester Weir, Prakasham Barrage, Jonval turbine, Tumbling Weir, Turgo turbine, Shiogo Dam, Phoenix breakwaters, Delaware Breakwater, Lagan Weir, Huntington Harbour, Huntington Beach, California, Ganges Barrage, Segner wheel, List of tidal barrages, Clarendon Weir, Barrage Vauban, Bincleaves Groyne. Excerpt: A water wheel is a machine for converting the energy of free-flowing or falling water into useful forms of power. A water wheel consists of a large wooden or metal wheel, with a number of blades or buckets arranged on the outside rim forming the driving surface. Most commonly, the wheel is mounted vertically on a horizontal axle, but the tub or Norse wheel is mounted horizontally on a vertical shaft. Vertical wheels can transmit power either through the axle or via a ring gear and typically drive belts or gears; horizontal wheels usually directly drive their load. Water wheels were still in commercial use well into the 20th century, but they are no longer in common use. Prior uses of water wheels include milling flour in gristmills and grinding wood into pulp for paper making, but other uses include foundry work and machining, and pounding linen for use in the manufacture of paper. Some water wheels are fed by water from a mill pond, which is formed when a flowing stream is dammed. A channel for the water flowing to or from a water wheel is called a mill race (also spelled millrace) or simply a "race", and is customarily divided into sections. The race bringing water from the mill pond to the water wheel is a headrace; the one carrying water after it has left the wheel is commonly referred to as a tailrace. The main difficulty of water wheels is their dependence on flowing water, which limits where they can be located. Modern hydroelectric dams can be viewed as the descendants of the water wheel as they too take advantage of the movement of water downhill. In water-raising devices rotary motion is typically more efficient than machines based on oscillating motion. In terms of power source, water wheels can be turned either by human or animal force or by the water current itself. Water wheels come in two basic designs, either equipped with a vertical or a horizontal axle. The latter type can be subdivided, depending on where the water hits the wheel paddles, into ove