Microtab dynamic modelling for wind turbine blade load rejection

A dynamic model characterising the effect of microtab deployment on the aerodynamics of its base aerofoil is presented. The developed model predicts the transient aerodynamic coefficients consistent with the experimental and computational data reported in the literature. The proposed model is then used to carry out investigation on the effectiveness of microtabs in load alleviation and lifespan increase of wind turbine blades. Simulating a bang–bang controller, different load rejection scenarios are examined and their effect on blade lifespan is investigated. Results indicate that the range of frequencies targeted for rejection can significantly impact the blade fatigue life. Case studies are carried out to compare the predicted load alleviation amount and the blade lifespan using the developed model with those obtained by other researchers using the steady state model. It is shown that the assumption of an instantaneous aerodynamic response as used in the steady state model can lead to inaccurate results

A decoupling control strategy for wind turbine blades equipped with active flow controllers

The use of active controls has shown to be of substantial help in supporting the increasing size of wind turbines by reducing peak stresses and fatigue loads. In this respect, this paper proposes the use of intuitive frequency-based control strategies for reducing loads in wind turbine blades equipped with multi-input multi-output (MIMO) active flow controllers. For that purpose, a loop-shaping approach is considered for analysing the dynamic of actively controlled wind turbine blades. Preliminary aeroelastic simulations are carried out to validate the results. It is shown that the MIMO vibration control problem can effectively be decomposed into a number of decoupled single-input single-output control problems because of the strong correlation between the dominant aeroelastic blade dynamics and actuator deployments. As a result, it is demonstrated that classical single-input single-output control systems can perform as efficiently as MIMO controllers for damping the aeroelastic dynamics of wind turbine blades

CAPTURE DES MÉSONS µ PAR LE CALCIUM-40

Nous effectuons le calcul du taux de capture total en utilisant les fonctions d'onde des noyaux obtenues a l'aide du modèle trou-particule. L'hypothèse U. F. I. et l'hypothèse du courant vectoriel conservé étendue au courant pseudo-scalaire induit permettent, par comparaison avec les résultats expérimentaux, d'obtenir une limite supérieure de la constante de couplage tensorielle induite.The total µ capture rate is calculated using nuclear wave functions obtained in the particle-hole model. The U. F. I. hypothesis and the theory of Conserved Vector Current (CVC) extended to induced pseudoscalar current give us, by cornparison with the experimental result, an approximative value of the tensor coupling constant gT