In connection with the use of high-head flat regulating gates the study of their vibrations in the stream becomes timely, Completed investigations [1-4] do not always permit an accurate analytical determination of the nature and magnitude of vibrational deformations of the gates, and the physical modeling of the process is quite difficult and involves distortion of the real phenomenon. Prototype investigations of the dynamics of the gate are therefore necessary.The main gate of the spillway of the XXII Congress CPSU, which is a welded triple 11 x 20 m structure [13], was selected as one of the objects of investigation. The gate operates under a static load with the partial openings from 0.5 to 4.0 m.For fiat, ribbed gates similar to those tested there is a theoretical method of determining the form and frequency of free fluctuations [5].With widely separated ribs and high rigidity of the gate in torsion the frequency of bending fluctuations is the smallest. This case is the most important because in actual gates small torsion deformations do not produce an appreciable effect on the frequency of free fluctuations.When the gate is immersed in the water the frequency of its free fluctuations decreases 1/q-n-fold, where n is the coefficient of increase of the mass of the fluctuating system due to the effect of the affected water mass.There are a number of papers on the determination of the affected water mass per unit length for fluctuation of fiat gates in a horizontal plane [8,11]. The recommended relationships are of the following form:The value of the coefficient K varies from 0.44 to 0.55 as was shown in ill].It is known that vibration of plane gates occurs in a submerged regime by the flow of water underneath the knife, i.e., as a rule, with gates located on a low spillway apron. Hydraulic conditions of flow around gates tocared on the crests of spillways of practical profiles are generally favorable, and pulsating loads on the gate are quite small (bending stresses caused by them on a given gate do not exceed 10 kg/cmZ). The purpose of this work was therefore to study the mechanism of the phenomenon, to check the theoretical method of determining the dynamic characteristics of a ribbed gate and of the magnitude of the affected water masses, and to investigate the reaction of the vibrating gate system to different dynamic disturbances: vibration of piers, aero-and hydrodynamic impulses, wave loads, etc. Accordingly, the experimental work consisted of two stages: 1) investigation of free vibrations of the gate in water and in air and determination of its dynamic characteristics; 2) investigation of the vibration of the gate under a head and with different gate openings.The following measuring methods were used in the course of the investigation: a) vibration sensors of various types (including mechanical and electromagnetic) for the registration of horizontal dynamic translocations of the gate and of the piers in the frequency range of 1.5-2.0 to 200 cycles. Electromagnetic vibration sensors of the *Deceased.
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