This is a major concern in gas turbine design, because the blades operate in the highly turbulent flow from the combustion chamber. A transient technique using liquid crystals has been developed for measuring heat transfer. We are studying the boundary layer on an acoustic liner with or without net transpiration, to obtain quantitative data for use in a prediction method. Prediction of surface pressure fluctuations Much of the noise in an airliner cabin is caused by pressure fluctuations in the boundary layer, which excite the skin panels.
Sound insulation is heavy and expensive.
We are adapting techniques used to compute the boundary layer velocity field, so that we can semi-empirically predict the frequency spectrum of the surface pressure fluctuations. Forms of boundary condition, and SGS models that limit smoothly into Reynolds-averaged models as the grid coarsens, are being evaluated using DNS results. Return to PB's Home Page .