In view of the uneven artificial sowing, low sowing, as well as the fact that the existing seeders cannot meet the sowing requirements of Pteris vittata, this paper designed an automatic plug seeder by using the method of spraying and sowing after mixing spores and water. In order to obtain the optimum working parameters of the seeder, response surface method (RSM) was employed to desi...

An experimental and numerical analysis of a low-angle annular expander nozzle is presented to observe the variance in shock structure within the flow field. A RANS-based axisymmetric numerical model was used to evaluate flow characteristics and the model validated using experimental pressure readings and schlieren images. Results were compared with an equivalent convergingdiverging nozzle to de...

To improve the calculation of the flow properties of an aerospike nozzle, different turbulence models were investigated in this study. The primary shape of the nozzle plug is determined through utilizing an approximate method. The flow field is, then, simulated using the Navier-Stokes equations for compressible flows. The commercial computational fluid dynamics code Fluent is used to simulate t...

The increased concern about environmental effect of off-target deposits of pesticides use has resulted in the development of numerous spray drift models. Statistical models based on experimental field studies are used to estimate off-target deposits for different sprayers in various environmental conditions. Random-walk and computational fluid dynamics (CFD) models have been used to predict the...

It has been suggested that rising bubbles in dense fluids resemble an inverted dripping faucet and that they undergo analogous period-doubling bifurcations to chaos. We present experimental results demonstrating that this analogy is weak because the dominant source of instability in the bubble train is inherently different mutual interactions between spatially separated bubbles as opposed to no...

Planar Laser-Induced Fluorescence PLIF is employed to measure rotational temperatures at the nozzle exit of a free-piston shock tunnel. The ow is at approximately Mach 7 and chemical eeects have been reduced by using a nitrogen test gas and low total enthalpy 5 MJJkg. Vibrational freezing in the nozzle expansion has an appreciable effect on the nozzle-exit rotational temperature, and therefore ...

An experimental investigation was performed of the acoustic effects of jet-pylon interaction for separate flow and chevron nozzles of both bypass ratio five and eight. The models corresponded to an approximate scale factor of nine. Cycle conditions from approach to takeoff were tested at wind tunnel free jet Mach numbers of 0.1, 0.2 and 0.28. An eight-chevron core nozzle, a sixteen chevron fan ...

A one-dimensional method-of-characteristics (MOC) code was developed to examine the venting of pulse detonation engines. Comparison with experimental results and twodimensional computational fluid dynamics demonstrates that a reasonably accurate level of simulation can be achieved with a single spatial dimension. A semi-empirical, deflagrative, flame-acceleration model was also constructed and ...

Measurements were made of the flow field structure and the near field parameters of a jet exhausting from a sonic nozzle with a 1.27 cm exit diameter. Compressed air was used for obtaining stagnation pressures up to ~ 5 atmospheres. The jet exhausted vertically from a settling chamber into an acoustically insulated room and through an insulated duct out through the roof. Measurements were made ...