We have recently shown that both the Prugniel-Simien model and Sérsic’s function (hereafter referred to as the Einasto model when applied to internal density profiles) describe simulated dark matter halos better than an NFW-like model with equal number of parameters. Here we provide analytical expressions for the logarithmic slopes of these models, and compare them with data from real galaxies....

We have recently shown that both the Prugniel-Simien model and Sérsic’s function (hereafter referred to as the Einasto model when applied to internal density profiles) describe simulated dark matter halos better than a NavarroFrenk-WhiteYlike model with an equal number of parameters. Here we provide analytical expressions for the logarithmic slopes of these models and compare themwith data from...

Study patterns of flow in pipes with rough walls can be considered relevant, as the use of rough surfaces is a method of heat transfer. In the theoretical study of heat transfer processes in heat exchangers and devices used in various fields of technology, it is very important to know the basic laws of flow in rough pipes in turbulent regime. Flow patterns for rough pipes differs from the behav...

We describe a simple method for estimating turbulent boundary layer wall friction using the fit of measured velocity data to a boundary layer model profile that extends the logarithmic profile all the way to the wall. Two 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 ...

Title of thesis: VELOCITY TRANSFORMATION FOR COMPRESSIBLE WALL TURBULENCE WITH HEAT TRANSFER Andrew Trettel, Master of Science, 2015 Thesis directed by: Professor Johan Larsson Department of Mechanical Engineering A transformation is derived that removes the effects of variable properties from wallbounded turbulent flows. The transformation derives from the logarithmic velocity profile and the ...

In the Manning equation the hydraulic radius can be defined as the cross-section dimension of the shape. In pipe flow the bed shear stress is assumed to be uniformly distributed along the wetted perimeter which cannot be true in open channel flow. Hence, three approximation of the true boundary shear-stress distribution are examined and more practical conveyance depth or resistance radius formu...

the estimation of velocity distribution plays a major role in the hydrodynamics of vegetated streams or rivers of extensive natural floodplains. the velocity profile in vegetated channels can be divided into three zones: uniform zone which is close to bed with uniform velocity distribution, logarithmic zone which involves the main channel with no vegetive cover and the transition zone that is a...

introduction: for a velocity profile in turbulent flows, the flow conditions in the vicinity of the wall are described by logarithmic law of the wall. however, it has been extensively verified that the log-law does not apply in the outer region of the boundary layer. for example, in free surface flows, the law of the wall holds only for 20 percent of the flow depth from the wall. coles (1956) c...