The steady, laminar, incompressible and two dimensional micropolar flow between two porous disks was investigated using optimal homotopy asymptotic method(OHAM) and fourth order Runge–Kutta numerical method. Comparis...The steady, laminar, incompressible and two dimensional micropolar flow between two porous disks was investigated using optimal homotopy asymptotic method(OHAM) and fourth order Runge–Kutta numerical method. Comparison between OHAM and numerical method shows that OHAM is an exact and high efficient method for solving these kinds of problems. The results are presented to study the velocity and rotation profiles for different physical parameters such as Reynolds number, vortex viscosity parameter, spin gradient viscosity and microinertia density parameter. As an important outcome, the magnitude of the microrotation increases with an increase in the values of injection velocity while it decreases by increasing the values of suction velocity.展开更多
The regional satellite navigation system of COMPASS (Phase I) provides both open services and authorized services. Authorized services offer differential corrections and integrity information to users to support highe...The regional satellite navigation system of COMPASS (Phase I) provides both open services and authorized services. Authorized services offer differential corrections and integrity information to users to support higher positioning, navigation and timing precision. Experimenting with real data, positioning accuracy is estimated with a 3GEO/4IGSO COMPASS constellation. The results show that with dual-frequency and single-frequency pseudo-range measurements, the positioning errors are respectively 8 and 10 m (RMS) for open service users, while for authorized users, the errors are 4 and 5 m (RMS), respectively. The COMPASS constellation geometry may cause large error to occur in the height component by 7-9 m for dualor single-frequency users, which can be effectively reduced with the differential corrections supplied by the authorized services. Multipath errors are identified and corrected for COMPASS, resulting in 25% positioning accuracy improvement for dual-frequency users and 10% improvement for single-frequency users.展开更多
文摘The steady, laminar, incompressible and two dimensional micropolar flow between two porous disks was investigated using optimal homotopy asymptotic method(OHAM) and fourth order Runge–Kutta numerical method. Comparison between OHAM and numerical method shows that OHAM is an exact and high efficient method for solving these kinds of problems. The results are presented to study the velocity and rotation profiles for different physical parameters such as Reynolds number, vortex viscosity parameter, spin gradient viscosity and microinertia density parameter. As an important outcome, the magnitude of the microrotation increases with an increase in the values of injection velocity while it decreases by increasing the values of suction velocity.
基金supported by the National Natural Science Foundation of China (Grant Nos. 11103064 and 11173049)the Shanghai Committee of Science and Technology, China (Grant No. 11ZR1443500)
文摘The regional satellite navigation system of COMPASS (Phase I) provides both open services and authorized services. Authorized services offer differential corrections and integrity information to users to support higher positioning, navigation and timing precision. Experimenting with real data, positioning accuracy is estimated with a 3GEO/4IGSO COMPASS constellation. The results show that with dual-frequency and single-frequency pseudo-range measurements, the positioning errors are respectively 8 and 10 m (RMS) for open service users, while for authorized users, the errors are 4 and 5 m (RMS), respectively. The COMPASS constellation geometry may cause large error to occur in the height component by 7-9 m for dualor single-frequency users, which can be effectively reduced with the differential corrections supplied by the authorized services. Multipath errors are identified and corrected for COMPASS, resulting in 25% positioning accuracy improvement for dual-frequency users and 10% improvement for single-frequency users.
