Modeling of stratosphere airship
The dynamics and kinematics model is very important for the analysis of stability, manipulation and control of stratosphere airship. A full modeling approach that includes the computation of aerodynamics of airship and the added mass for the nonlinear dynamics simulation of stratosphere airships is proposed in this paper. In this approach, the aerodynamics of airship is calculated based on a panel method, an engineering estimation and theory approach. A new numerical method for calculating added masses of airship is developed by using the CFD method. This model can simulate the motion of stratosphere airships quickly and accurately.
Modeling and Simulation of Airship Dynamics
This paper proposes a modeling approach for the nonlinear dynamics simulation of airships. The flight mechanics, aerostatics, and aerodynamics are incorporated into the model. A comprehensive estimation method is provided for the aerodynamics, including added-mass terms, viscous effect, forces on the fins, forces on the hull due to the fins, and axial drag. A simulation program is developed from the dynamics model and applied to analyze the control responses of the Skyship-500 airship. A comparison between the simulation and flight test results for different control inputs shows that the dynamics simulation gives a reasonable estimation of the flight behavior. The dynamics model is then linearized using a finite difference approach and the linear model is applied to investigate the stability of longitudinal and lateral motion at various speeds. With the trust gained from validation, the dynamics model and simulation program can be used to evaluate the flight and control performance of other airships.
Laminar heat or mass transfer in rectangular channels and in cylindrical tubes for fully developed flow: comparison of solutions obtained for various boundary conditions
Abstract A comparison is made of results obtained with various boundary conditions at the wall of the channels. By comparing blood Sherwood numbers for finite wall resistance with those for constant concentration boundary condition only a small variation is found for various points along the blood channel.