No abstract

The fundamental aerodynamic characteristics of a paraglider's canopy are investigated in wind tunnel experiments using an inflatable cell model designed to represent the dynamic behaviors of each cell comprising the canopy. At attack angles greater than a few degrees, the cell model inflates fully. To characterize its aerodynamic characteristics, we focus our attention on the flow around the inflated cell model at the plane of symmetry of the model. The cross-sectional profile of the inflated cell model, streamline pattern, internal air pressure and external surface pressure distribution are measured at various attack angles in order to identify the function of air intake and to obtain the lift and drag coefficients of the airfoil with an open air intake. The results reveal the mechanism of how the cell inflates into a stable wing shape and bears the buckling force caused by the cables suspending a pay load.

To determine the parameters which can improve the overall performance of a paraglider wing canopy, we have been investigating the fundamental aerodynamic characteristics of an inflatable cell model which is designed to represent the dynamic behaviors of each cell comprising the wing canopy. This paper describes the results of a series of wind tunnel experiments. It is shown that significant drag reduction can be achieved by adopting an appropriately designed shape for the soft cloth comprising the upper surface. A trade-off relationship between the aerodynamic quality (characterized by the lift-to-drag ratio) and structural strength (characterized by the internal air pressure coefficient) of the canopy is also examined in detail.

The aerodynamic characteristics of paraglider canopy cells were examined using an inflatable cell model with rigid ribs, which was proposed in our previous paper. The model is constructed by rapping the side edges of an appropriately shaped thin vinyl sheet along the perimeter of two parallel airfoil-shaped rigid ribs, and the wind tunnel experiment utilizing it represents a cell of an infinite array of identical cells placed in a uniform stream. The three-dimensional, inflated surface profile and surface pressure distribution of an inflatable cell model with a large air-intake opening were measured to characterize aerodynamic characteristics due to the inflation of upper and lower surfaces. The underlying physics were also explored in detail.

In this study, the influences of different parameters on performance of a heat pipe with stainless steel net as wick have been presented. Experiments have been carried out for an input power range from 80 W to 160 W, constant cooling water mass flow rate of 0.0515 liter/s, and constant temperature at the inlet to condenser of 11°C. The temperatures were recorded at different power level by using a laser thermometer of the heater block, evaporator and condenser end at 50 second interval. Variation in the input power was done by varying the input voltage. It was done by a variack. Considering all criteria the copper is selected as the material of the container, water is selected as the working fluid of the heat pipe, stainless steel net is used as wick material. As copper/water heat pipes are able to tolerate storage temperatures between -65°C and 250°C, and can effectively operate between 10°C and 250°C. So a .9144 m copper tube is used to construct the heat pipe. Inside this tube stainless steel net is used as wick material to aid the flow of fluid. In the observation it is observed that the temperature of the evaporator end increases at a greater rate of the copper pipe than the heat pipe at different power level. It has been shown the variation of temperature of the heater block and the evaporator section at 80V, 100V, 120V, 140V, 160V respectively of the heat pipe and copper pipe.