Top Of Car Research Articles

Aerodynamic characteristics of a super high-speed elevator with different toe guards

To reduce the drag and noise of a super high-speed elevator, a certain type of elevator in operation with different toe guards was taken as the subject to conduct research on its aerodynamic characteristics. In this study, a numerical simulation model was established and used to carry out experiments, and by comparing the theoretical and experimental results, the validity of the method was verified. First, a 3-D unsteady numerical model was established based on improved unstructured dynamic grid method, and the Reynolds average N–S equation was solved by SIMPLEC algorithm. Then, the whole running process of the elevator was simulated, including the velocity distribution, vorticity strength, and pressure gradient in the flow field were analyzed. Finally, the aerodynamic characteristics of the elevator with different vertical heights and four structure layouts of the toe guard were analyzed. The results show that the drag reduction effect is quite apparent when toe guards are installed at the car's top and bottom. In addition, it was found that decreasing the vertical height of the toe guard is conducive to reducing resistance and saving space in the elevator car. The inclusive analysis not only explores the aerodynamic characteristics of super high-speed elevators but also recommends structural optimization design.

Skin Friction Coefficient on a Yarn Package Surface in Ring Spinning

The skin friction coefficient on the surface of a rotating yarn package affects the power required to drive the package. This paper examines the relationship between the skin friction coefficient on the package surface and its diameter and rotating speed, based on the fundamentals of aerodynamics and the experimental results of power consumption. Skin friction coefficients on the surfaces of an airplane, car top, and yarn package are discussed. The results indicate that the skin friction coefficient on the package surface without hairiness depends on the package diameter and spindle speed only. The skin friction coefficient on the yarn package surface is about three times that on the top surface of a car, and is about twenty times that on an airplane surface. The power consumed to overcome skin friction drag is more than that consumed to drive the spindle if the spindle speed is very slow. However, the situation reverses when the spindle speed is fast.

Wanathamulla: aid to utilities planning

graphy is simple. Flying a microlight is uncomplicated, on certain types of microlight a trainee can fly safely within a few hours. Many microlights are portable (car top or trailer), and can be assembled within an hour. They do not require airport facilities for take-off and landing, but can be operated from very nearby the project area (football fields, pastures, roads, tracks can all serve as airfields). They are cheap to purchase ($5 000-10 000) and to operate. It would be conceivable for ‘they do not require airport facilities for take-off and carding’

Studies on Structure and Function on the Rice Ear : IV. Classification of ear type by number of grain on the secondary rachis-branch

Varietal Variations in the structure of ear and the size of grain were examined on thirty-two varieties, belonging to the different ecotypes. Five types of ear were classified principally based on the differences in number of grains on the secondary rachis-branch with the nodal position of the primary rachis-branch on a rachis (Fig. 1). Ear type I: The number of grains on the secondary rachis-branch was numerous in basal position of the car and became less towards the top of car. Ear type III: The number of grains on the secondary rachis-branch was also numerous in the middle position of car. And car type V: the number of grains on the secondary rachis-branch was numerous in the upper position of ear and became less towards the basal position. Two intermediate types, i.e., ear type II and IV were set in betwen type I and III, and type III and V, respectively. Indica varieties, which had larger total number of grains per ear than others, belonged to ear type III-V. Large grain varietics, which were larger in grain size than others, belonged to ear type I-II, and japonica cultivars belongcd to ear type I-III (Table 1, Fig. 2 and 3). The primary rachis-branch was numbered acropetally. The ratio of a nodal number of the primary rachis-branch having the maximum number of grains on the secondary rachis-branch to total number of the primary rachis-branch per ear was in the range of 4.3-3.8 in type I, 3.8-2.8 in type II, 2.6-1.9 in type III, 1.9-1.6 in type IV and below 1.6 in type V (Fig. 1). In a previous paper (SASAHARA, et al., 1982), it was reported that increasing rate of car weight at the maximum increasing period was higher in indica and large grain varieties than in japonica ones. Therefore, it may be concluded that indica varieties in which the grains on the secondary rachis-branch would have recieved the effect of apical dominance due to their abundant existence in the upper position of ear, and may result in increased rate of ear dry weight. On the other hand, in large grain varieties the less grain number in the upper position of ear could be compensated by the large grain size, resulting in high increasing rate of ear dry weight similar to indica varieties.