Laminar Drag Reduction

Drag reduction is an area of research and development in fluid mechanics, where the energy efficiency of fluid transport systems can be improved by controlling fluid flows. For example, one can reduce the fuel consumption of aircraft, ships, trains and motorcars by applying different drag reduction technologies. Here, using less fuel does not only imply less emissions of harmful gases to environment, but also lead to a reduced noise level, contributing much to an enrichment of the quality of life. The Advisory Council for Aviation Research and Innovation in Europe (ACARE) has recently published the EU’s vision for future aviation, where CO₂ and NOx emissions should be reduced by 75% and 90%, respectively by the year 2050, accompanied by a noise reduction of 65%.

Drag reduction can be obtained by controlling either turbulent or laminar flows. Turbulent drag reduction has been an active area of research, where turbulence can be supressed by flow surface modifications such as riblets, or drag-reducing additives such as long-chain polymers and surfactants. The latter is the drag reduction technique that the author of this book has extensively investigated over past years.