Sökning: "Blade Passing Frequency"

Visar resultat 1 - 5 av 8 avhandlingar innehållade orden Blade Passing Frequency.

  1. 1. Investigation of Tonal Noise Sources from Centrifugal Fan using Detached Eddy Simulation

    Författare :Martin Ottersten; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Computational aeroacoustics; Blade passing frequency; Centrifugal fan; Low-frequency rotation; Tonal noise.;

    Sammanfattning : Since we spend the majority of our time indoors, heating, ventilation, and air conditioning (HVAC) systems have become a more and more important part of many people´s life. They provide a sufficient amount of airflow with the correct temperature, quality, and humidity. LÄS MER

  3. 2. Numerical investigation of tonal noise sources from centrifugal fan

    Författare :Martin Ottersten; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Computational Aeroacoustics; Tonal Noise; Centrifugal Fan; Blade Passing Frequency;

    Sammanfattning : Heating, ventilating, and air conditioning systems (HVAC) are today an important part of many people's life. They provide a sufficient amount of airflow with the correct temperature, quality, and humidity. The negative side is the noise it produces. Many improvements have been made in building development to reduce noise from the environment. LÄS MER

  4. 3. Numerical Investigation of Aerodynamic Blade Excitation Mechanisms in Transonic Turbine Stages

    Författare :Björn Laumert; KTH; []
    Nyckelord :Transonic Turbines; CFD; Forced Response; Unsteady Aerodynamics;

    Sammanfattning : With the present drive in turbomachine engine developmenttowards thinner and lighter bladings, closer spaced blade rowsand higher aerodynamic loads per blade row and blade, advanceddesign criteria and accurate prediction methods for vibrationalproblems such as forced response become increasingly importantin order to be able to address and avoid fatigue failures ofthe machine early in the design process. The present worksupports both the search for applicable design criteria and thedevelopment of advanced prediction methods for forced responsein transonic turbine stages. LÄS MER

  5. 4. Numerical studies of receptivity, stability and transition of wing and turbine blade boundary layers

    Författare :Luca De Vincentiis; Ardeshir Hanifi; Dan S. Henningson; Stefania Cherubini; KTH; []
    Nyckelord :Teknisk mekanik; Engineering Mechanics;

    Sammanfattning : In the present thesis, receptivity, stability and laminar-turbulent transition of different boundary-layer flows are addressed and investigated by means of direct numerical simulations. In particular, flows over a wing and a low-pressure-turbine (LPT) blade have been the main focus. LÄS MER

  7. 5. Stability and transition on wind turbine blades

    Författare :Thales Coelho Leite Fava; Ardeshir Hanifi; Dan Henningson; Stefania Cherubini; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Boundary layer stability; free-stream turbulence; laminar-turbulent transition; low-frequency oscillations; rotation effects; wind turbine blades.; Gränsskiktsstabilitet; friströmsturbulens; laminär-turbulent omslag; lågfrekventa svängningar; rotationseffekter; vindkraftverksblad.; Teknisk mekanik; Engineering Mechanics;

    Sammanfattning : Transition on wind turbine blades is a highly complex phenomenon due to the myriad effects influencing the process. This thesis studies some of them, namely free-stream turbulence (FST), rotation, and three-dimensionality. The investigations employ large eddy simulations (LES) with and without (implicit or wall-resolved LES) a subgrid-scale model. LÄS MER