OTT L A

GERMANY (see also List of Individuals)

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7.3.1883 Kempten/D - 16.3.1946 Kempten/D

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Ludwig Albert Ott, son of Albert (1847-1895), and his brother took over the family firm in 1895. The two developed hydraulic instrumentation, among which special note refers to the current meter.

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Current meters were for a long time the only means to determine local flow velocity in natural rivers. Although the Pitot tube had been developed almost at the same time, Reinhard Woltman's (1757-1837) invention remains up today the standard gauging instrument. By lowering a propeller into a flow, the number of revolutions determines the flow velocity. The discharge can be determined with the integral method as the sum of elementary discharges across a river profile. The first successful observations were conducted by André Baumgarten (1808-1859) on Garonne River. Later, his method was improved by Andreas Harlacher (1842-1890) on Elbe River, among others. Adolf Thiem (1836-1908) installed in 1898 a current meter on a water main in Leipzig for permanent discharge reading, whereas Josef Epper (1855-1924) set up around 1900 an outdoor station for the accurate rating of current meters. The Ott family was known for precise fabrication of mechanical instruments, among which Ludwig was the designer of the Ott current meters that became famous. Each meter was individually rated in an in-house towing tank with a counting method being perfected in parallel. The device was connected to a battery with a clock ringing after a certain number of propeller revolutions. The relation between this number and the water velocity is linear, involving two experimentally determined constants. Ott designed also especially large current meters for low speed flow, such as those installed in Bavaria's Walchensee power plant in 1924. He also contributed to an improved meter rating and may be considered a mechanical engineer perfecting an important hydraulic instrument.

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_{Anonymous (1990). Über 100 Jahre Präzision aus Kempten. Wasserwirtschaft 80(5): 256-258. Kolupaila, S. (1960). Water measurement in hydraulic structures. La Houille Blanche 15(4): 344-363. P}

_{Ott, L.A. (1924). Wassermessungen bei Wasserkraftanlagen. Wasserkraft-Jahrbuch 1924: 253-}

_{282. Pflaum: München.}

_{Ott, L.A. (1925). Theorie und Konstantenbestimmung des hydrometrischen Flügels. Springer: Berlin.}

_{Ott, L.A. (1931). Instrumentenkunde der praktischen Hydrometrie. Ott: Kempten.}

_{Ott, L.A. (1932). Ausfluss, Durchfluss und Überfall. Wasserkraft und Wasserwirtschaft 27(18): 205-210.}