Mohammad Reza Kavian Pour, H.r. Masoumi ,
Volume 6, Issue 3 (9-2008)
Abstract
Hydraulics of stepped spillway is a very complicated phenomenon, as it consists of a two phase flow passing through a set of designed steps. The steps increase the rate of energy dissipation taking place on the spillway face. Turbulence, flow aeration and energy dissipation are the main tasks in the design of such structures. This study consists of the experimental investigation to determine the energy dissipation over stepped spillways. Experiments conducted at Water Research Institute on two physical models of the Siyah Bisheh stepped spillways in Iran. To develop a more generalized expression, the results of previous investigations were also considered in our study. Therefore, a wide range of variables were taken into account to estimate the energy dissipation along the non-uniform flow regime. Assuming the energy dissipation along the uniform flow regime to be equal to the vertical displacement of the jet, the total energy lost was calculated. A comparison of the results with those of measurements showed a regression of 0.92 for the total energy dissipation, which is one of the features of the present method for estimating of the energy dissipation, compared with the previous investigation.
Ziba Fazel, Masoome Fazelian, Dr. Hamed Sarkardeh,
Volume 15, Issue 2 (3-2017)
Abstract
Air-water flow is a complex and challenging subject in many engineering fields as well as hydraulic engineering and discovery of its characteristics can help the engineers to predict and analyze a probable phenomenon. In the present paper, development of a device capable of measuring the flow velocity, air concentration, diameter and counts of bubbles in air-water flows is described. The heart of the present device is two resistive probes with a novel configuration. Being pressure and corrosion resistant and also having negligible resistivity in the flow are some of the unique features of the employed needles. Moreover, sampling frequency and time can be set for the intended application by the user. In the present electronic board, maximum available sampling frequency is in the order of KHz, while the time of sampling is not limited. The circuit is designed with ability for avoiding the polarization of the probe tip. Increasing the number of probes up to four which can operate together and suitable for more complex flows with no change in the electronic board is another advantage of the proposed device. Different tests for verification of the device accuracy have been performed and good results were reported for measurements.
