The Experts below are selected from a list of 135 Experts worldwide ranked by ideXlab platform

Boris Arcen - One of the best experts on this subject based on the ideXlab platform.

  • Prediction of a particle-laden turbulent channel flow: Examination of two classes of stochastic dispersion Models
    International Journal of Multiphase Flow, 2014
    Co-Authors: Anne Tanière, Boris Arcen
    Abstract:

    Nowadays, two families of stochastic Models are mainly used to predict the dispersion of inertial particles in inhomogeneous turbulent flows. This first one is named ``Normalized Model'' and the second one ``Generalized Langevin Model (GLM)''. Nevertheless, the main differences between the Normalized and GLM Models have not been thoroughly investigated. Is there a Model which is more suitable to predict the particle dispersion in inhomogeneous turbulence? We propose in the present study to clarify this point by computing a particle-laden turbulent channel flow using a GLM-type Model, and also a Normalized-type Model. Particle statistics (such as concentration, mean and rms particle velocity, fluid-particle velocity covariances) will be provided and compared to Direct Numerical Simulation (DNS) data in order to assess the performance of both dispersion Models. It will be shown that the Normalized dispersion Model studied can predict correctly the effect of particle inertia on some dispersion statistics, but not on all. For instance, it was found that the prediction of the particle kinetic shear stress and some components of the fluid-particle covariance is not physically acceptable.

  • Prediction of a particle-laden turbulent channel flow: GLM and Normalized stochastic Models
    2013
    Co-Authors: Anne Tanière, Boris Arcen
    Abstract:

    Nowadays, two families of stochastic Models are mainly used to predict the dispersion of inertial particles in inhomogeneous turbulent flows. This first one is named "Normalized Models" and the second one "GLM Models". Nevertheless, the main differences between the Normalized and GLM Models have not been thoroughly investigated. Is there a Model which is more suitable to predict the particle dispersion in inhomogeneous turbulence? We propose in the present study to clarify this point by computing a particle-laden turbulent channel flow using the GLM Model proposed by Arcen and Taniere [1] and the Normalized Model recently used by Dehbi [2]. Particle statistics (such as mean and rms particle velocity) will be provided and compared to direct numerical simulation (DNS) data in order to assess the performance of both dispersion Models. It will be shown that the Normalized dispersion Model studied can predict correctly the effect of particle inertia on some dispersion statistics, but not on all. For instance, ...

Anne Tanière - One of the best experts on this subject based on the ideXlab platform.

  • Prediction of a particle-laden turbulent channel flow: Examination of two classes of stochastic dispersion Models
    International Journal of Multiphase Flow, 2014
    Co-Authors: Anne Tanière, Boris Arcen
    Abstract:

    Nowadays, two families of stochastic Models are mainly used to predict the dispersion of inertial particles in inhomogeneous turbulent flows. This first one is named ``Normalized Model'' and the second one ``Generalized Langevin Model (GLM)''. Nevertheless, the main differences between the Normalized and GLM Models have not been thoroughly investigated. Is there a Model which is more suitable to predict the particle dispersion in inhomogeneous turbulence? We propose in the present study to clarify this point by computing a particle-laden turbulent channel flow using a GLM-type Model, and also a Normalized-type Model. Particle statistics (such as concentration, mean and rms particle velocity, fluid-particle velocity covariances) will be provided and compared to Direct Numerical Simulation (DNS) data in order to assess the performance of both dispersion Models. It will be shown that the Normalized dispersion Model studied can predict correctly the effect of particle inertia on some dispersion statistics, but not on all. For instance, it was found that the prediction of the particle kinetic shear stress and some components of the fluid-particle covariance is not physically acceptable.

  • Prediction of a particle-laden turbulent channel flow: GLM and Normalized stochastic Models
    2013
    Co-Authors: Anne Tanière, Boris Arcen
    Abstract:

    Nowadays, two families of stochastic Models are mainly used to predict the dispersion of inertial particles in inhomogeneous turbulent flows. This first one is named "Normalized Models" and the second one "GLM Models". Nevertheless, the main differences between the Normalized and GLM Models have not been thoroughly investigated. Is there a Model which is more suitable to predict the particle dispersion in inhomogeneous turbulence? We propose in the present study to clarify this point by computing a particle-laden turbulent channel flow using the GLM Model proposed by Arcen and Taniere [1] and the Normalized Model recently used by Dehbi [2]. Particle statistics (such as mean and rms particle velocity) will be provided and compared to direct numerical simulation (DNS) data in order to assess the performance of both dispersion Models. It will be shown that the Normalized dispersion Model studied can predict correctly the effect of particle inertia on some dispersion statistics, but not on all. For instance, ...

J. Qiu - One of the best experts on this subject based on the ideXlab platform.

  • Comparison of electromagnetic and piezoelectric vibration energy harvesters: Model and experiments.
    Sensors and Actuators A: Physical, 2012
    Co-Authors: Emmanuelle Arroyo, Adrien Badel, Fabien Formosa, J. Qiu
    Abstract:

    A Normalized Model for piezoelectric and electromagnetic vibration energy harvesters is described, allowing a unique expression of the harvested power to be written. The normalization used points out three characteristic parameters of any generator: its coupling coefficient, its losses coefficient and its mechanical quality factor. The evolution of the Normalized harvested power is theoretically studied as a function of these parameters. Experimental results and a bibliographic study present typical orders of magnitude of coupling and losses coefficients values for piezoelectric and electromagnetic generators, and put forward unusual dualities: while piezoelectric generators have low coupling and low losses coefficients, electromagnetic generators exhibit high resistive losses compensated by high coupling coefficients. For both generators almost the same Normalized power can be harvested with these dual parameters. Finally, the scaling effect is investigated: it is notably shown that the power density of an electromagnetic generator does not decrease proportionately with its volume as it is commonly accepted.

Emmanuelle Arroyo - One of the best experts on this subject based on the ideXlab platform.

  • Modeling and design of an electromagnetic vibration energy harvester and its dedicated energy extraction circuit.
    2012
    Co-Authors: Emmanuelle Arroyo, Adrien Badel, Fabien Formosa
    Abstract:

    This work investigates the design of an electromagnetic generator including its energy extraction and conditioning circuit. The Normalized Model of an electromagnetic generator points out three dimensionless parameters, characteristic of the generator. The power harvested with the SMFE (Synchronized Magnetic Flux Extraction) circuit is theoretically calculated and compared to the power extracted with a conventional approach. Optimal parameters orders of magnitude are pointed out for each technique, and a literature review shows that existing electromagnetic generators parameters are not suitable to harvest the maximum Normalized power. Based on these considerations the design of an electromagnetic generator adapted to the SMFE technique is proposed. The results of the optimization predicts a theoretical harvested power of 19 mW for an external vibration acceleration of 2g, and a resonance frequency of 100 Hz.

  • Comparison of electromagnetic and piezoelectric vibration energy harvesters: Model and experiments.
    Sensors and Actuators A: Physical, 2012
    Co-Authors: Emmanuelle Arroyo, Adrien Badel, Fabien Formosa, J. Qiu
    Abstract:

    A Normalized Model for piezoelectric and electromagnetic vibration energy harvesters is described, allowing a unique expression of the harvested power to be written. The normalization used points out three characteristic parameters of any generator: its coupling coefficient, its losses coefficient and its mechanical quality factor. The evolution of the Normalized harvested power is theoretically studied as a function of these parameters. Experimental results and a bibliographic study present typical orders of magnitude of coupling and losses coefficients values for piezoelectric and electromagnetic generators, and put forward unusual dualities: while piezoelectric generators have low coupling and low losses coefficients, electromagnetic generators exhibit high resistive losses compensated by high coupling coefficients. For both generators almost the same Normalized power can be harvested with these dual parameters. Finally, the scaling effect is investigated: it is notably shown that the power density of an electromagnetic generator does not decrease proportionately with its volume as it is commonly accepted.

Fabien Formosa - One of the best experts on this subject based on the ideXlab platform.

  • Modeling and design of an electromagnetic vibration energy harvester and its dedicated energy extraction circuit.
    2012
    Co-Authors: Emmanuelle Arroyo, Adrien Badel, Fabien Formosa
    Abstract:

    This work investigates the design of an electromagnetic generator including its energy extraction and conditioning circuit. The Normalized Model of an electromagnetic generator points out three dimensionless parameters, characteristic of the generator. The power harvested with the SMFE (Synchronized Magnetic Flux Extraction) circuit is theoretically calculated and compared to the power extracted with a conventional approach. Optimal parameters orders of magnitude are pointed out for each technique, and a literature review shows that existing electromagnetic generators parameters are not suitable to harvest the maximum Normalized power. Based on these considerations the design of an electromagnetic generator adapted to the SMFE technique is proposed. The results of the optimization predicts a theoretical harvested power of 19 mW for an external vibration acceleration of 2g, and a resonance frequency of 100 Hz.

  • Comparison of electromagnetic and piezoelectric vibration energy harvesters: Model and experiments.
    Sensors and Actuators A: Physical, 2012
    Co-Authors: Emmanuelle Arroyo, Adrien Badel, Fabien Formosa, J. Qiu
    Abstract:

    A Normalized Model for piezoelectric and electromagnetic vibration energy harvesters is described, allowing a unique expression of the harvested power to be written. The normalization used points out three characteristic parameters of any generator: its coupling coefficient, its losses coefficient and its mechanical quality factor. The evolution of the Normalized harvested power is theoretically studied as a function of these parameters. Experimental results and a bibliographic study present typical orders of magnitude of coupling and losses coefficients values for piezoelectric and electromagnetic generators, and put forward unusual dualities: while piezoelectric generators have low coupling and low losses coefficients, electromagnetic generators exhibit high resistive losses compensated by high coupling coefficients. For both generators almost the same Normalized power can be harvested with these dual parameters. Finally, the scaling effect is investigated: it is notably shown that the power density of an electromagnetic generator does not decrease proportionately with its volume as it is commonly accepted.