Blar i NTNU Open på forfatter "Østby, Petter Thorvald Krogh"

Viser treff 1-5 av 5

    • Damping Measurements on a Multi-Blade Cascade with Multiple Degrees of Freedom: A Francis-99 Test Case 

      Bergan, Carl Werdelin; Tengs, Erik Os; Solemslie, Bjørn Winther; Østby, Petter Thorvald Krogh; Dahlhaug, Ole Gunnar (Journal article; Peer reviewed, 2019)
      Due to thinner blades and higher demands for flexibility, the high-head Francis runners designed today face considerable challenges that severely affect the runners' expected lifetime. For many high-head Francis runners, ...

    • Experimental investigation on the effect off near walls on the eigen frequency of a low specific speed francis runner 

      Østby, Petter Thorvald Krogh; Sivertsen, Kjell; Billdal, Jan Tore; Haugen, Bjørn (Journal article; Peer reviewed, 2019)
      The importance to correctly predict the natural frequency of a turbine runner have been demonstrated several times. It is now common practice to include the added mass effect of the surrounding water when calculating the ...

    • Experimental Study of a Low-Specific Speed Francis Model Runner during Resonance 

      Agnalt, Einar; Østby, Petter Thorvald Krogh; Solemslie, Bjørn Winther; Dahlhaug, Ole Gunnar (Journal article; Peer reviewed, 2018)
      An analysis of the pressure in a runner channel of a low-specific speed Francis model runner during resonance is presented, which includes experiments and the development of a pressure model to estimate both the convective ...

    • Fluid structure interaction of Francis-99 turbine and experimental validation 

      Østby, Petter Thorvald Krogh; Agnalt, Einar; Haugen, Bjørn; Billdal, Jan Tore; Dahlhaug, Ole Gunnar (Journal article; Peer reviewed, 2019)
      The ability to predict a francis runners dynamic response to the exciting forces is paramount to avoid unwanted disintegration of the turbines components. In this article, each of the principal factors contributing to the ...

    • On the External Effects Affecting Torsional Modes in Guide Vanes 

      Østby, Petter Thorvald Krogh; Myrvold, Eivind; Jan Tore, Billdal; Haugen, Bjørn (Journal article; Peer reviewed, 2019)
      Rotor stator interaction in high-head Francis turbines has led to several failures in recent years. Increasing efficiency demands require design optimization of the turbine components, which may lead to thinner profiles. ...