Johann Nikuradse (original) (raw)
Johann Nikuradse (ივანე ნიკურაძე, Ivane Nikuradze; * 20. November 1894 in Samtredia; † 18. Juli 1979) war ein in Georgien geborener, deutscher Ingenieur und Physiker. Johann Nikuradse war der Bruder des Physikers Alexander Nikuradse.
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| dbo:abstract | Johann Nikuradse (ივანე ნიკურაძე, Ivane Nikuradze; * 20. November 1894 in Samtredia; † 18. Juli 1979) war ein in Georgien geborener, deutscher Ingenieur und Physiker. Johann Nikuradse war der Bruder des Physikers Alexander Nikuradse. (de) Johann Nikuradse (Georgian: ივანე ნიკურაძე, Ivane Nikuradze) (November 20, 1894 – July 18, 1979) was a Georgia-born German engineer and physicist. His brother, Alexander Nikuradse, was also a Germany-based physicist and geopolitician known for his ties with Alfred Rosenberg and for his role in saving many Georgians during World War II. He was born in Samtredia, Georgia (then part of the Kutais Governorate, Imperial Russia) and studied at Kutaisi. In 1919, through the recommendations of the conspicuous Georgian scholar Petre Melikishvili, he went abroad for further studies. The 1921 Sovietization of Georgia precluded his return to homeland and Nikuradse naturalized as a German citizen. As PhD student of Ludwig Prandtl in 1920, he later worked as a researcher at the Kaiser Wilhelm Institute for Flow Research (now the Max Planck Institute for Dynamics and Self-Organization). He succeeded in putting himself in Prandtl's favour and thus advanced to the position of department head. In spite of his close ties with the Nazi Party, Nikuradse came, in the early 1930s, under fire of the institute's National Socialist Factory Cell Organization whose members accused him of spying for the Soviet Union and of stealing books from the institute. Prandtl initially defended Nikuradse, but was eventually forced to dismiss him in 1934. He then served as a professor at the University of Breslau (1934–1945), and an honorary professor at the Aachen Technical University since 1945. Nikuradse lived mostly in Göttingen and engaged in hydrodynamics. His best known experiment was published in Germany in 1933. Nikuradse carefully measured the friction that a turbulent fluid experiences as it flows through a rough pipe. He used grains of sand with varying roughnesses and discovered that, the rougher the surface the greater the friction, and hence a greater pressure loss. He discovered that: In range I, for small Reynolds number the resistance factor is the same for rough as for smooth pipes. The projections of the roughening lie entirely within the laminar layer for this range.In range II (transition range), an increase in the resistance factor was observed for an increasing Reynolds number. The thickness of the laminar layer is here of the same order of magnitude as that of the projections.In range III, the resistance factor is independent of the Reynolds number (quadratic law of resistance). Here all the projections of the roughening extend through the laminar layer and the resistance factor . (en) Ivan (naturalisé en Johann) Nikuradzé (ივანე ნიკურაძე, Ivane Nikuradze ; né le 20 novembre 1894 à Samtredia ; † 18 juillet 1979) est un ingénieur hydraulicien allemand d’origine géorgienne. Avec son frère, le physicien et géopolitologue , il fut en relation avec Alfred Rosenberg et joua un rôle considérable dans le sauvetage de plusieurs réfugiés géorgiens au cours de la Seconde Guerre mondiale. (fr) Johann Nikuradse, nato Ivane Nikuradze (in georgiano: ივანე ნიკურაძე?; Samtredia, 20 novembre 1894 – 18 luglio 1979), è stato un ingegnere e fisico georgiano naturalizzato tedesco. Ricavò una legge per valutare l'attrito idraulico per moti in condotte rugose; inoltre insieme a suo fratello , fisico e geopolitologo, collaborò con Alfred Rosenberg aiutando numerosi oppositori georgiani nel corso della seconda guerra mondiale. (it) Johann Nikuradse (ივანე ნიკურაძე, Ivane Nikoeradze) (Samtredia, 20 november 1894 – Göttingen, 18 juli 1979) was een Duits ingenieur en fysicus geboren in Georgië. Johann Nikuradse was de broer van de natuurkundige . Dit was ook een in Duitsland wonende natuurkundige en geopoliticus die bekend stond om zijn banden met Alfred Rosenberg en om zijn rol bij het redden van veel Georgiërs tijdens de Tweede Wereldoorlog. Het schijnt dat Johann al op 14-jarige leeftijd naar Tartu in het Gouvernement Riga ging, en bij een oudere broer, Silovan Nikoeradze ging wonen. In de literatuur komen verschillende geboortedata voor. Hij was daar echter officieel niet als student was ingeschreven . De geboortedatum vermeld in het proefschrift van Nikuradse is vrijwel zeker fout . Volgens Hager & Liiv hebben de Estse archieven geen documenten met betrekking tot Johann. Als hij met Silovan in Tartu was geweest, zou Nikuradse te jong zijn geweest om daar te hebben gestudeerd. Het lijkt daarom dat Nikuradse bij zijn inschrijving aan de universiteit van Göttingen ten onrechte heeft beweerd te hebben gestudeerd in Tartu. In het CV bij zijn proefschrift vermeldt hij het geboortejaar 1892; 2 jaar eerder dan in de officiële documenten. Een van de redenen waarom Johann Nikuradse zich ouder deed voorkomen, was zijn angst om in het Russische leger te worden ingelijfd. In Rusland en later in de Sovjet-Unie was er een systeem dat garandeerde dat universiteitsstudenten alleen zouden worden opgeroepen tijdens noodsituaties. Tussen 1915 en 1917, toen de situatie voor Rusland kritisch werd, werd hij gemobiliseerd. Hij is uiteindelijk afgestudeerd als ingenieur aan het polytechnisch instituut in Tblisi in 1919. Daarna ging hij naar Duitsland. Vermoedelijk is 1894 correct, maar heeft hij zich later ouder voorgedaan om op deze wijze net te doen of hij rond 1910 al studeerde om zo de dienstplicht in de Sovjet-Unie te ontlopen. (nl) Johann Nikuradse (em georgiano: ივანე ნიკურაძე, Ivan Nikuradze; Samtredia, 20 de novembro de 1894 — 18 de julho de 1979) foi um engenheiro e físico nascido na Geórgia. Seu irmão, , foi também um físico e geopolítico baseado na Alemanha, conhecido por seus laços com Alfred Rosenberg e por sua atuação salvando muitos georgianos durante a Segunda Guerra Mundial. Nasceu em Samtredia, Geórgia (na época parte da , Império Russo), e estudou em Kutaisi. Em 1919, por recomendação de , foi estudar no exterior. A invasão soviética da Geórgia em 1921 impediu seu regresso à pátria, e Nikuradse naturalizou-se cidadão alemão. Aluno de doutorado de Ludwig Prandtl em 1920, trabalhou depois como pesquisador no Kaiser-Wilhelm-Institut für Strömungsforschung (atualmente ), sendo depois por decisão de Prandtl seu diretor. Apesar de seus laços estreitos com o Partido Nazista, no início da década de 1930 Nikuradse foi acusado pelos membros do de espionagem para a União Soviética e de roubar livros do instituto. Prandtl inicialmente defendeu-o, mas foi forçado a demití-lo em 1934. Foi então professor na Universidade de Wrocław (1934–1945), e foi professor honorário da Universidade Técnica de Aachen a partir de 1945. Nikuradse viveu principalmente em Göttingen e envolveu-se com hidrodinâmica. Seu mais famoso experimento foi publicado na Alemanha em 1933. Nikuradse mediu cuidadosamente o atrito a que um fluido turbulento é submetido quando flui descendo em um tubo áspero. Ele usou grãos de areia de diferentes rugosidades e descobriu que quanto maior a rugosidade, maior a fricção, e, então, a perda de pressão também aumenta. Ele descobriu que: Na faixa I, para pequenos números de Reynolds o fator de resistência é o mesmo para tubos rugosos ou lisos. As projeções da rugosidade ficam inteiramente dentro da camada laminar para esta faixa.Na faixa II (intervalo de transição) um aumento do factor de resistência foi observado para um número de Reynolds crescente. A espessura da camada laminar é aqui da mesma ordem de magnitude que a das projeçõesNa faixa III, o factor de resistência é independente do número de Reynolds (lei quadrática de resistência). Aqui todas as projeções da rugosidade se estendem através da camada laminar e o factor de resistência (pt) |
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| rdfs:comment | Johann Nikuradse (ივანე ნიკურაძე, Ivane Nikuradze; * 20. November 1894 in Samtredia; † 18. Juli 1979) war ein in Georgien geborener, deutscher Ingenieur und Physiker. Johann Nikuradse war der Bruder des Physikers Alexander Nikuradse. (de) Ivan (naturalisé en Johann) Nikuradzé (ივანე ნიკურაძე, Ivane Nikuradze ; né le 20 novembre 1894 à Samtredia ; † 18 juillet 1979) est un ingénieur hydraulicien allemand d’origine géorgienne. Avec son frère, le physicien et géopolitologue , il fut en relation avec Alfred Rosenberg et joua un rôle considérable dans le sauvetage de plusieurs réfugiés géorgiens au cours de la Seconde Guerre mondiale. (fr) Johann Nikuradse, nato Ivane Nikuradze (in georgiano: ივანე ნიკურაძე?; Samtredia, 20 novembre 1894 – 18 luglio 1979), è stato un ingegnere e fisico georgiano naturalizzato tedesco. Ricavò una legge per valutare l'attrito idraulico per moti in condotte rugose; inoltre insieme a suo fratello , fisico e geopolitologo, collaborò con Alfred Rosenberg aiutando numerosi oppositori georgiani nel corso della seconda guerra mondiale. (it) Johann Nikuradse (Georgian: ივანე ნიკურაძე, Ivane Nikuradze) (November 20, 1894 – July 18, 1979) was a Georgia-born German engineer and physicist. His brother, Alexander Nikuradse, was also a Germany-based physicist and geopolitician known for his ties with Alfred Rosenberg and for his role in saving many Georgians during World War II. He discovered that: (en) Johann Nikuradse (ივანე ნიკურაძე, Ivane Nikoeradze) (Samtredia, 20 november 1894 – Göttingen, 18 juli 1979) was een Duits ingenieur en fysicus geboren in Georgië. Johann Nikuradse was de broer van de natuurkundige . Dit was ook een in Duitsland wonende natuurkundige en geopoliticus die bekend stond om zijn banden met Alfred Rosenberg en om zijn rol bij het redden van veel Georgiërs tijdens de Tweede Wereldoorlog. Het schijnt dat Johann al op 14-jarige leeftijd naar Tartu in het Gouvernement Riga ging, en bij een oudere broer, Silovan Nikoeradze ging wonen. In de literatuur komen verschillende geboortedata voor. Hij was daar echter officieel niet als student was ingeschreven . De geboortedatum vermeld in het proefschrift van Nikuradse is vrijwel zeker fout . Volgens Hager & Liiv hebben de E (nl) Johann Nikuradse (em georgiano: ივანე ნიკურაძე, Ivan Nikuradze; Samtredia, 20 de novembro de 1894 — 18 de julho de 1979) foi um engenheiro e físico nascido na Geórgia. Seu irmão, , foi também um físico e geopolítico baseado na Alemanha, conhecido por seus laços com Alfred Rosenberg e por sua atuação salvando muitos georgianos durante a Segunda Guerra Mundial. Ele descobriu que: (pt) |
| rdfs:label | Johann Nikuradse (de) Ivan Nikuradzé (fr) Johann Nikuradse (it) Johann Nikuradse (en) Johann Nikuradse (nl) Johann Nikuradse (pt) Іване Нікурадзе (uk) |
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