wind flow

In general, rotating objects always produce different rotational torques according to different dimensions and rotational speeds. In some cases, it can cause a lot of damage to equipment, so it is necessary to be aware of the amount of torque that rotating objects produce at different rotational speeds, as well as in the presence or absence of air flow. in this study, numerical and experimental analysis of non-continuous flow around a cylindrical model with vertical plates under forced rotation is performed and its main purpose is to measure the torque of rotating objects in the presence of wind current also to stabilize rotation. Rotational speeds are constant. First, an aerodynamic torque measuring device was built and then a 3-fin cylindrical model was tested in a wind tunnel, and numerical simulations of 3 and 2 fin models were performed in the same laboratory conditions by Ensys Fluent software. A good agreement was observed between the experimental and numerical results and the maximum error between them was less than 10%, which is acceptable. From the simulation results, it was observed that in every 180 degrees of rotation that the maximum cross section of the models is exposed to direct wind flow, the maximum torque produced by the 2-blade cylindrical model is 30% higher than the maximum torque produced by the 3-blade model. As the wind speed increases from 20 to 60 meters per second, the torque of the 3-fin model increases from 0.4 to 1.2 Nm, which is equivalent to 200%.

In the present study, the two-dimensional lock-exchange turbidity current under the influence of wind flow is modeled using open-source software. To solve this, the large eddy simulation method has been used in order to observe turbulent phenomena more accurately. By developing the two-phase solver of the software so that the equations of the volume of fluid method are coupled with the scalar equation of concentration, the three-phase problem is simulated as a phase of a mixture of dense fluid and pure water next to the air phase. The results show that an increase in wind speed reduces the buoyancy force driving the turbidity current and increases the entrainment, which means faster pollution of water areas. This increase in wind speed also increases the wall shear stress, with the difference that the amount of wall shear stress at low wind speeds is not significant. So this prevents a significant change in the deposition behavior of the current. Studying the current's sedimentation behavior, showed that at high wind speeds, the co-current wind flow corresponding to the turbidity current has more harmful effects than the reverse wind flow and its sediment accumulation is getting higher.