The large-eddy simulation(LES)with the dynamic Smagorinsky model is used to predict the interior sound of an idealized vehicle cabin under the excitation of the wall pressures from turbulent channel flows.In compariso...The large-eddy simulation(LES)with the dynamic Smagorinsky model is used to predict the interior sound of an idealized vehicle cabin under the excitation of the wall pressures from turbulent channel flows.In comparison with direct numerical simulation(DNS),the LES results overpredict the sound pressure level(SPL)at low frequencies and underpredict the SPL at high frequencies.The incorrect predictions result from the incorrect prediction of LES on surface pressures,where the LES over-estimates the wavenumber and frequencies spectra of surface pressures at small wavenumbers and frequencies and under-estimates the spectra at large wavenumbers and frequencies.However,the LES results are close to the filtered-DNS results,implying that the unresolved scales are also important to surface pressures and interior sound.The Euler-Bernoulli beam under the excitation of exterior pressures,which serves as a simple model for aero-vibro-acoustics in the case of hydrodynamical fast,is used to explain the observed predictions and show that the Corcos model cannot represent the variation of turbulence pressure spectra at wavenumbers and frequencies.Therefore,the new requirement for the LES method,when applied to fluid-structural-acoustic interaction problems at high Reynolds numbers,is the correct prediction of wavenumber and frequency spectra of turbulence wall pressure.展开更多
At present, the further development of new energy vehicles industry is hindered by limited consumer's participation or capital investment. Therefore, a new multilateral model of cross-industry alliance needs to ar...At present, the further development of new energy vehicles industry is hindered by limited consumer's participation or capital investment. Therefore, a new multilateral model of cross-industry alliance needs to arise. The advanced charging technology of Internetdistributed mobile energy can link up with many market participants closely and form an effective and multilateral win-win cross-industry alliance. This new industry alliance can realize unexpected multiple goals, for example,(1)consumers who have purchased new energy vehicles can avail free charging;(2) potential vehicle buyers can be encouraged to use new energy vehicles;(3) the new energy vehicle manufacturers can expand their production scale;(4) the new energy vehicles sellers(4 S shop) can expand their sales volume;(5) large shopping malls can attain more income;(6) financial institutions can absorb more deposits;(7) governments can further promote low-carbon traffic. This article analyzes the cross-industry alliance and its forming mechanism.1)展开更多
Auto-Making Plan China is aiming to become an automaking powerhouse in a decade,boosting the development of newenergy vehicles(NEVs)and relaxing restrictions on foreign ownership.The strategy is to achieve breakthroug...Auto-Making Plan China is aiming to become an automaking powerhouse in a decade,boosting the development of newenergy vehicles(NEVs)and relaxing restrictions on foreign ownership.The strategy is to achieve breakthroughs in key technologies and increase the share of Chinese brands in the international auto market by 2025,according to an auto industry development plan released on April 25 by three government departments including the Ministry of Industry and Information Technology.展开更多
基金Basic Science Center Program of the National Natural Science Foundation of China for“Multi-scale Problems in Nonlinear Mechanics”(Grant No.11988102)National Key Project(Grant No.GJXM92579).
文摘The large-eddy simulation(LES)with the dynamic Smagorinsky model is used to predict the interior sound of an idealized vehicle cabin under the excitation of the wall pressures from turbulent channel flows.In comparison with direct numerical simulation(DNS),the LES results overpredict the sound pressure level(SPL)at low frequencies and underpredict the SPL at high frequencies.The incorrect predictions result from the incorrect prediction of LES on surface pressures,where the LES over-estimates the wavenumber and frequencies spectra of surface pressures at small wavenumbers and frequencies and under-estimates the spectra at large wavenumbers and frequencies.However,the LES results are close to the filtered-DNS results,implying that the unresolved scales are also important to surface pressures and interior sound.The Euler-Bernoulli beam under the excitation of exterior pressures,which serves as a simple model for aero-vibro-acoustics in the case of hydrodynamical fast,is used to explain the observed predictions and show that the Corcos model cannot represent the variation of turbulence pressure spectra at wavenumbers and frequencies.Therefore,the new requirement for the LES method,when applied to fluid-structural-acoustic interaction problems at high Reynolds numbers,is the correct prediction of wavenumber and frequency spectra of turbulence wall pressure.
文摘At present, the further development of new energy vehicles industry is hindered by limited consumer's participation or capital investment. Therefore, a new multilateral model of cross-industry alliance needs to arise. The advanced charging technology of Internetdistributed mobile energy can link up with many market participants closely and form an effective and multilateral win-win cross-industry alliance. This new industry alliance can realize unexpected multiple goals, for example,(1)consumers who have purchased new energy vehicles can avail free charging;(2) potential vehicle buyers can be encouraged to use new energy vehicles;(3) the new energy vehicle manufacturers can expand their production scale;(4) the new energy vehicles sellers(4 S shop) can expand their sales volume;(5) large shopping malls can attain more income;(6) financial institutions can absorb more deposits;(7) governments can further promote low-carbon traffic. This article analyzes the cross-industry alliance and its forming mechanism.1)
文摘Auto-Making Plan China is aiming to become an automaking powerhouse in a decade,boosting the development of newenergy vehicles(NEVs)and relaxing restrictions on foreign ownership.The strategy is to achieve breakthroughs in key technologies and increase the share of Chinese brands in the international auto market by 2025,according to an auto industry development plan released on April 25 by three government departments including the Ministry of Industry and Information Technology.
