We compare measured profiles of upper layer shear and rates of kinetic energy dissipation with the predictions of a one-dimensional turbulence model proposed by Craig and Banner (1994). Their formulation contains an unknown parameter, the "roughness length" z0, which we determine by fitting computed and observed dissipation rates. The resulting model, without further adjustment, is then used to...

An air–sea interaction model that includes turbulent transport due to capillary waves (surface ripples) is developed. The model differs from others in that the physical premises are applicable to low wind speeds (10-m wind speed, U10 , 5 m s21) as well as higher wind speeds. Another new feature of the model is an anisotropic roughness length, which allows a crosswind component of the stress to ...

The Colorado State University standard mesoscale model is used to evaluate the sensitivity of one-dimensional (1D) and two-dimensional (2D) fields to differences in surface-layer parameterization “constants”. Such differences reflect the range in the published values of the von Karman constant, Monin-Obukhov stability functions and the temperature roughness length at the surface. The sensitivit...

Various studies investigating the future impacts of integrating high levels of renewable energy make use of historical meteorological (met) station data to produce estimates of future generation. Hourly means of 10m horizontal wind are extrapolated to a standard turbine hub height using the wind profile power or log law and used to simulate the hypothetical power output of a turbine at that loc...

In-service the degradation of compressor blade leading edges can have a disproportional effect on compressor efficiency. The high surface curvature in this region makes quantifying the surface finish of this sensitive and prominent region difficult. An automated technique that characterises the roughness of the leading edge in terms of areal parameters is presented. A set of ex-service blades o...

Results of the study of surface roughness of the aircraft engine blade model, produced with various methods of rapid prototyping are presented. Blade models were made with two incremental methods of rapid prototyping: stereo lithography (SLA-250 device) and three-dimensional printing (Z510 Spectrum printer). In incremental methods of rapid prototyping a model is formed by hardening of consecuti...

The effects of hull and propeller roughness are presented over ten years operation on ship performance. developed model used in this study is a combination NavCad Matlab to perform the resistance propulsion computations selected as well processing input output data. By considering hull, engine installed an optimized propeller, performance computed for different according ITTC recommendations op...

Literature review indicates that a large amount of failures are caused by abnormal wear of the diesel engine components. It is therefore essential to monitor the engine condition using the tribological information. Although the wear debris analysis has been proven to be effective for condition monitoring and fault diagnosis (CMFD) of diesel engines, limited work has been done to address the rem...

Current internal combustion engine technology for road vehicles allows us to meet the existing and planned future standards for emission. However, the motion of a moving vehicle used in real operating conditions is frequent changes of the values of power in the powertrain. The analysis of the results of the road test through a measurement of parameters of engine in a passenger car proves, that ...

We propose a long-term parameterization scheme for two critical parameters, zero-plane displacement height (d) and aerodynamic roughness length (z0m), that we further use in the Surface Energy Balance System (SEBS). A sensitivity analysis of SEBS indicated that these two parameters largely impact the estimated sensible heat and latent heat fluxes. First, we calibrated regression relationships b...