The present paper follows our previous work in which a coupling approach of smoothed particle hydrodynamics （SPH） and element bending group （EBG） was developed for modeling the interaction of viscous incompressibl...The present paper follows our previous work in which a coupling approach of smoothed particle hydrodynamics （SPH） and element bending group （EBG） was developed for modeling the interaction of viscous incompressible flows with flexible fibers. It was also shown that a flexible object may experience drag reduction because of its reconfiguration due to fluid force on it. However, the reconfiguration of deformable bodies does not always result in drag reduction as different deformation patterns can result in different drag scales. In the present work, we studied the bending modes of a flexible fiber in viscous flows using the presented SPH and EBG coupling approach. The flexible fiber is immersed in a fluid and is tethered at its center point, while the two ends of the fiber are free to move. We showed that the fiber undergoes four different bending modes： stable U-shape, slight swing, violent flapping, and stable closure modes. We found there is a transition criterion for the flexible fiber from slight swing, suddenly to violent flapping. We defined a bending number to characterize the bending dynamics of the interaction of flexible fiber with viscous fluid and revealed that this bending number is relevant to the non-dimensional fiber length. We also identified the critical bending number from slight swing mode to violent flapping mode.展开更多
Exploiting the thermal insulation properties of glass fiber and excellent conductivity of conducting polymer, a novel one-dimensional (1D) composite thermoelectric material, based on poly(3,4-ethylenedioxythiophene): ...Exploiting the thermal insulation properties of glass fiber and excellent conductivity of conducting polymer, a novel one-dimensional (1D) composite thermoelectric material, based on poly(3,4-ethylenedioxythiophene): p-toluenesulfonic acid (PEDOT: p-TSA)/glass fiber, is prepared by coating the PEDOT: p-TSA on the surface of glass fiber with in situ polymerization method. We hope the materials can bring out the performance of the “electron conductor, photon glass”. During the polymerization process, the effects of oxidant concentration and dopant mass fraction on thermoelectric properties of the materials are investigated. The group type of the polymer chain and the morphology of the samples were characterized by Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM), respectively. The maximal Seebeck coefficient (S) and electric conductivity (σ) of the pristine sample are 32 μVK-1 and 169 Sm-1, respectively. After further post-processing with methanol, the thermoelectric properties of materials were improved, and the maximum value of S and σ increased greatly to 48.5 μVK-1 and 3184 Sm-1, respectively. The maximal power factor (PF) of materials also increased from 0.12 μWm-1 K-2 to 6.74 μWm-1 K-2. Moreover, we have proposed a preliminary explanation on the carrier transport mechanism.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11302237,11172306 and U1530110)
文摘The present paper follows our previous work in which a coupling approach of smoothed particle hydrodynamics （SPH） and element bending group （EBG） was developed for modeling the interaction of viscous incompressible flows with flexible fibers. It was also shown that a flexible object may experience drag reduction because of its reconfiguration due to fluid force on it. However, the reconfiguration of deformable bodies does not always result in drag reduction as different deformation patterns can result in different drag scales. In the present work, we studied the bending modes of a flexible fiber in viscous flows using the presented SPH and EBG coupling approach. The flexible fiber is immersed in a fluid and is tethered at its center point, while the two ends of the fiber are free to move. We showed that the fiber undergoes four different bending modes： stable U-shape, slight swing, violent flapping, and stable closure modes. We found there is a transition criterion for the flexible fiber from slight swing, suddenly to violent flapping. We defined a bending number to characterize the bending dynamics of the interaction of flexible fiber with viscous fluid and revealed that this bending number is relevant to the non-dimensional fiber length. We also identified the critical bending number from slight swing mode to violent flapping mode.
文摘Exploiting the thermal insulation properties of glass fiber and excellent conductivity of conducting polymer, a novel one-dimensional (1D) composite thermoelectric material, based on poly(3,4-ethylenedioxythiophene): p-toluenesulfonic acid (PEDOT: p-TSA)/glass fiber, is prepared by coating the PEDOT: p-TSA on the surface of glass fiber with in situ polymerization method. We hope the materials can bring out the performance of the “electron conductor, photon glass”. During the polymerization process, the effects of oxidant concentration and dopant mass fraction on thermoelectric properties of the materials are investigated. The group type of the polymer chain and the morphology of the samples were characterized by Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM), respectively. The maximal Seebeck coefficient (S) and electric conductivity (σ) of the pristine sample are 32 μVK-1 and 169 Sm-1, respectively. After further post-processing with methanol, the thermoelectric properties of materials were improved, and the maximum value of S and σ increased greatly to 48.5 μVK-1 and 3184 Sm-1, respectively. The maximal power factor (PF) of materials also increased from 0.12 μWm-1 K-2 to 6.74 μWm-1 K-2. Moreover, we have proposed a preliminary explanation on the carrier transport mechanism.
