COBEM99

S21 Vibrações e Análise Modal

Titulo:

APLICATION OF CONVENTIONAL DATA ASSIMILATION METHODS IN ROTORDYNAMICS

Resumo :

DATA ASSIMILATION METHODS ARE WIDELY APPLIED IN CLIMATIC FORECASTING. NUMERICAL METHEOROLOGICAL PREDICTIONS ARE MADE BY SOLVING DIFFERENTIAL EQUATIONS WHICH DESCRIBE THE CLIMATIC BEHAVIOR. AS THESE DIFFERENTIAL EQUATIONS ARE THEORETICAL ONES IT IS NECESSARY TO IMPOSE CONVENIENT INITIAL CONDITIONS AND REMOVE ERRORS DURING THE INTEGRATION PROCESS. THIS IS MADE BY DATA ASSIMILATION METHODS. THE PROBLEM IS QUITE SIMILAR IN ROTORDYNAMICS: THE MOTION IS ALSO GOVERNED BY DIFFERENTIAL EQUATIONS. TWO FACTOR, HOWEVER, MAKE THE PROBLEM MORE COMPLEX IN ROTORDYNAMICS: A) ROTOR MOTION, ONLY CAN USUALLY BE MONITORED IN A FEW MEASUREMENT POINTS AND THESE VALUES MUST BE EXTRAPOLATED FOR ALL VARIABLES; B) THE FREE VIBRATION REQUIRES THE SOLUTION OF A COMPLEX EIGENVELUE PROBLEM AND THE COMPLEX AIGENVECTORS WILL BE USED IN INITIALIZATION METHOD. THE INITIALIZATION METHOD CONSISTS IN PROCESSING THE INITIAL CONDITIONS TO FILTER NO SIGINIFICANT MODES AND THE DYNAMIC RELAXATION AND OPTIMAL INTERPOLATION METHODS USE MEASUREMENTS TO UP TO DATE INTEGRATION RESULTS. THIS WORK PRESENTS NA ADAPTATION OF INITIALIZATION, DYNAMIC RELAXATION AND OPTIMAL INTERPOLATION METHODS, CONSIDERED CONVENTIONAL DATA ASSIMILATION METHOS IN METHEOROLOGICAL SCIENCES TO ROTORDYNAMICS. SOME RESULTS OF THE APPLICATION OF THE INITIALIZATION AND DYNAMIC RELAXATION METHODS IN A VERTICAL ROTOR MODEL WHICH SIMULATES THE BEHAVIOR OF A FRANCIS TURBINE WERE OBTAINED AND COMPARED WITH DIRECT INTEGRATION OF DIFFERENTIAL EQUATIONS. A PRELIMINAR EVALUATION OF THESE RESULTS WAS POSITIVE SHOWING THAT THESE TOOLS MAY BE POWERFUL IN SIMULATION OF ROTATING AND STRUCTURAL SYSTEMS. PALAVRAS-CHAVE: DATA ASSIMILATION, ROTORDYNAMICS, INITIALIZATION, DYNAMIC RELAXATION, OPTIMAL INTERPOLATION.

Autores :

Piccoli, Humberto Camargo

Trabalho Completo :