The geometrical coupling between strain and twist in double helices is investigated. Overwinding, where strain leads to further winding, is shown to be a universal property for helices, which are stretched along their longitudinal axis when the initial pitch angle is below the zero-twist angle (39.4◦). Unwinding occurs at larger pitch angles. The zero-twist angle is the unique pitch angle at th...

In this paper, three dimensional flow characteristic was presented by a revision of an impeller of an axial turbo fan for improving the airflow rate and the static pressure. TO consider an incompressible steady three-dimensional flow, the RANS equations are used as the governing equations, and the standard k-ε turbulence model is chosen. The pitch angles of 44°, 54°, 59°, and 64° are implemente...

The article presents the results of research on operation a wind microturbine model with an adjustable blade pitch angle. physical basics turbine and methods its optimal control are discussed. measurements carried out for selected geometry possibility adjusting angle presented. tests were resistive load linear characteristic non-linear Li-Po battery. simple MPPT algorithm practical controlling ...

Plate heat exchangers are widely used in industries due to their special characteristics, such as high thermal efficiency, small size, light weight, easy installation, maintenance, and cleaning. The purpose of this study is to consider the effect of depth, angle, and pitch of hemispheric Chevrons on the convective heat transfer coefficient and pressure drop. In the simulation of the heat ex...

Plate heat exchangers are widely used in industries due to their special characteristics, such as high thermal efficiency, small size, light weight, easy installation, maintenance, and cleaning. The purpose of this study is to consider the effect of depth, angle, and pitch of hemispheric Chevrons on the convective heat transfer coefficient and pressure drop. In the simulation of the heat ex...

Flapping insect flight is a complex and beautiful phenomenon that relies on fast, active control mechanisms to counter aerodynamic instability. To directly investigate how freely flying Drosophila melanogaster control their body pitch angle against such instability, we perturbed them using impulsive mechanical torques and filmed their corrective maneuvers with high-speed video. Combining experi...