Papers by Author: Ke Yang

Abstract: According to the general solution for waterhammer deriving by the author, this paper proved that the solution can be written in the form of the d'Alembert's wave functions. Some equations including the so-called the chain equation is derived with the help of the new solution. The periodical influence of the initial conditions on the results is discussed.

Abstract: The paper has obtained a unified final solution for the waterhammer equations. The proposed solution, covering all kinds of initial conditions and boundary conditions, has been proved to be written in the form of the d'Alembert's wave functions. The periodical influence of the initial conditions on the results is discussed. The proposed solution, with two kinds of algebraic equations containing only finite terms, is suitable for numerical calculation, convenient for programming and liable to dealing with complex pipe systems. An example has been given to show the use of the method. The skill to perform the inverse Laplace transform in obtaining the solution is different from the traditional ones and can be extended to use in many other problems including the FSI waterhammer problem.

Abstract: This paper presents field measurement results of boundary layer wind characteristics over typical open country during the passages of typhoon Fung-wong passed by Wenzhou in July 2008. The field data such as wind speed and wind direction were measured from two propeller anemometers placed at the height of about 30m. The measured wind data are analyzed to obtain the information on mean wind speed and direction, turbulence intensity, gust factor, turbulence integral length scale and spectra of wind speed fluctuations. The results clearly demonstrate that the turbulence intensity and gust factor of typhoon Fung-wong are larger than normal, and there is a tendency for the turbulence intensities to decrease with the increase of the mean wind speed, however, there is another tendency for the turbulence integral length scale to increase with the increase of the mean wind speed. The power spectral densities of fluctuating wind speed in longitudinal and lateral directions obtained from the measured wind speed data roughly fit with Von Karman spectra. The results presented in this paper are expected to be of use to researchers and engineers involved in design of low-rise buildings.