Laminar Flow Control - Back to the Future?

The paper was presented at 38th Fluid Dynamics Conference and Exhibit ,23 - 26 June 2008, Seattle, Washington. – In the 21st Century, reducing the environmental impact of aviation will become an increasingly important priority for the aircraft designer. Among the various environmental impacts, emission of CO2 can be expected to emerge as the most important in the long term and reducing fuel burn to become the overriding environmental priority. Increasing fuel costs and the world’s limited oil reserves will add to the pressure to reduce fuel burn. Starting from the limitations imposed on the aircraft designer by the laws of physics – the Breguet Range Equation, the Second Law of Thermodynamics, the behaviour of real, viscous fluids – the paper discusses the technological and design options available to the designer. Improvements in propulsion and structural efficiency have valuable contributions to make but it is in drag reduction through laminar flow control that the greatest opportunity lies. The physics underlying laminar flow control is discussed and the key features and limitations of natural, hybrid and full laminar flow control are explained.