The influence of water environment on natural frequencies of a Francis pump-turbine runner with the shaft is analyzed. The computations are executed by ANSYS program package based on finite element method. The fluid ‘equivalent mass‘ matrix concept is used. For solution, the Euler approach is used. Obtained natural frequencies and vibration mode shapes of the turbine runner with shaft in vaccum, in air and in water are presented. Computed natural frequencies and vibration mode shapes of the turbine runner with shaft in vacuum are compared to computed natural frequencies and vibration mode shapes of the turbine runner without shaft. and Obsahuje seznam literatury
A detailed analysis of dynamical properties of five-blade-bundle mathematical model was carried out with the aim to investigate how the damping elements made of rubber inserted into slots between blades heads influence the response curves at different distribution of exciting harmonic forces. Viscous-elastic linear Voigt-Kelvin model was used for modeling the rheological properties of damping elements. Constant values of stiffness and damping parameters were supposed at analysis. The orthogonality of excitation forces distribution to the other eigenmodes of blades bundle is applied at insulated selected resonance. and Obsahuje seznam literatury
In the paper there are deduced differential equations of the vibroisolation system of the ambulance couch. The kinematic excitation is realized in three directions: the vertical translation and the rotations around the both horizontal axes of the car. The suspension of the ambulance couch corresponds to this presumption and is made by the parallelogram; on the upper base there is a double level Cardan suspension.
The linearised system of the motion equations is stated and the preliminary analysis of the dependency of all the three natural frequencies on the selected parameters is made. By vertical kinematics excitation numerical simulation of the excited oscillations is made. and Obsahuje seznam literatury
This study seeks to derive an original multicriterial decision making model for operative control of water quality in the water reservoir. The model design is based on the theory of dynamic systems control. It incorporates simulation modelling methods with the hydrodynamic reservoir and multicriterial optimization methods. The research aims to derive an algorithm for operating rules of the reservoir under any operating conditions and for the given criteria of control. The study presents the outcomes of the application of model quality control of water withdrawal from the Římov reservoir on the Malše River. and Studie odvozuje původní vícekriteriální rozhodovací model pro operativní řízení kvality odebírané vody z vodárenské nádrže. Model vychází z teorie řízení dynamických systémů a propojuje se v něm metodologie simulačního modelování s hydrodynamikou nádrží a metodami vícekriteriální optimalizace. Cílem řešení je odvodit algoritmus pro regulační zásahy (manipulace) na nádrži při libovolných provozních podmínkách a pro stanovená kritéria řízení. Studie uvádí výsledky aplikace modelového řízení kvality vody v nádrži Římov na Malši.