Sökning: "propulsive efficiency"

Visar resultat 1 - 5 av 12 avhandlingar innehållade orden propulsive efficiency.

  1. 1. Roller skis' rolling resistance and grip characteristics : influences on physiological and performance measures in cross-country skiers

    Författare :Mats Ainegren; Peter Carlsson; Marko Laaksonen; Mittuniversitetet; []
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Adjustable grip; blood lactate; centre of pressure; cycle length; cycle rate; economy; efficiency; friction coefficient; heart rate; normal force; OBLA; oxygen uptake; power; ratcheted wheel; ratings of perceived exertion; roller skis; rolling resistance; tangential force; time to exhaustion;

    Sammanfattning : The aim of this thesis was to investigate roller ski characteristics; classical and freestyle roller skis’ rolling resistance coefficients (μR) and classical style roller skis’ static friction coefficients (μS), and to study the influence of different μR and μS on cross-country skiers’ performance and both physiological and biomechanical indices. The aim was also to study differences in skiing economy and efficiency between recreational skiers, female and male junior and senior elite cross-country skiers. LÄS MER

  3. 2. Large Area Propellers

    Författare :Daniel Knutsson; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; propeller hull interaction; propulsive efficiency; large propellers;

    Sammanfattning : Even if shipping is the most energy efficient and inexpensive way of transporting large volumes of goods across the world, it still could be significantly improved with respect to energy efficiency.In this thesis, propulsive efficiency is improved by moving the propeller backwards from its original position and increasing its diameter. LÄS MER

  4. 3. Aviation and the Environment- Evaluation of High Propulsive Efficiency Engines

    Författare :Linda Larsson; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Aircraft engine; Environment; Open rotor; Turbofan; Aviation;

    Sammanfattning : There has been more than a tenfold increase in passenger kilometers traveled over the last 40 years. The highest rate of growth today is in developing countries such as China and India. These countries also have the two largest populations in the world. LÄS MER

  5. 4. Numerical optimization of hull/propeller/rudder configurations

    Författare :Kaijia Han; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; fuel cost savings; optimization; pressure fluctuation; self-propulsion; RANS; verification and validation; cavitation; open water; lifting surface; hull-propeller-rudder; effective wake; efficiency; aspect ratio; lifting line; interaction;

    Sammanfattning : The new framework of the global economy has stimulated and expanded the shipbuilding and shipping industry, especially in Asia in the twenty-first century. This induces urgent and high requirements on designing and building both conventional and new types of ships with high performance, such as high speed, manoeuvrability, seaworthiness and so on. LÄS MER

  7. 5. Towards Environmentally Friendly Aero Engines

    Författare :Rickard Avellan; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; geared turbofan; energy efficiency; turbofan; environmentally friendly; DDTF; aero engines; GTF; aircraft;

    Sammanfattning : Since the introduction of subsonic jet driven commercial aircraft, incremental improvements in overall efficiency has been a driving requirement as well as a selling argument for the engine industry. The historical overall efficiency improvement is the result of continuous advances in aerodynamic design, increase of overall pressure ratios, turbine inlet temperatures and propulsive efficiencies in parallel with the development of stronger and lighter materials. LÄS MER