Development of turbulent boundary layers past a step change in wall roughness
نویسندگان
چکیده
منابع مشابه
A Method for Estimating Wall Friction in Turbulent Boundary Layers
We describe a simple method for estimating wall friction which uses the fit of velocity data to the boundary layer profile in wall units all the way from the wall to the end of the log region. Two different models for the boundary layer profile are examined, the power-series interpolation scheme of Spalding and the Musker profile which is based on the eddy viscosity concept. The accuracy of the...
متن کاملA Wall Law for Two-Phase Turbulent Boundary Layers
Abstract—The presence of bubbles in the boundary layer introduces corrections into the log law, which must be taken into account. In this work, a logarithmic wall law was presented for bubbly two phase flows. The wall law presented in this work was based on the postulation of additional turbulent viscosity associated with bubble wakes in the boundary layer. The presented wall law contained empi...
متن کاملNear-wall cycle amplitude modulation in turbulent boundary layers
A non-linear influence of the large-scale log-region motions onto the small-scale near-wall cycle is found to exist in the buffer and log-region of turbulent boundary layers. Based on recent observations of Hutchins & Marusic (2007b) in high Reynolds number turbulent boundary layers, a novel procedure is developed to evaluate the modulation effect. This is done using tools based on Hilbert tran...
متن کاملRough-wall turbulent boundary layers with constant skin friction
A semi-empirical model is presented that describes the development of a fully developed turbulent boundary layer in the presence of surface roughness with length scale ks that varies with streamwise distance x. Interest is centred on flows for which all terms of the von Kármán integral relation, including the ratio of outer velocity to friction velocity U+ ∞ ≡ U∞/uτ , are streamwise constant. F...
متن کاملInstabilities in turbulent boundary layers
An investigation of a model of turbulence generation in the wall region of a turbulent boundary layer is made through direct numerical simulations. The model is based on the instability of a streak. First, a laminar boundary layer disturbed by a continuous blowing through a slot is simulated in order to reproduce and further investigate the results reported from the experiments of Acarlar & Smi...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Journal of Fluid Mechanics
سال: 2016
ISSN: 0022-1120,1469-7645
DOI: 10.1017/jfm.2016.213