Computational Analysis of the Rotating Cylinder Embedment onto Flat Plate

The Magnus effect and its evolution have greatly affected the aerospace industry over the past century to date. Nevertheless, cylinder embedment onto a flat plate offers a new discovery that is yet to be investigated, specifically whether the concept could enhance the aerodynamic properties of the flat plate following the Magnus effect momentum injection. Over the past decade, the use of a rotating cylinder on an aerofoil has existed from past researches studies where the embedment has significantly increased in its aerodynamic performance better than the one without Magnus application. However, it would be hard to achieve experimental-wise as an accurate measurement and fabrication would be needed to have the same resulting effects. Here, most of the researchers would not focus deeply on the placement of the cylinder as this may increase their fabrication and testing complications. Therefore, the current study delineates the use of flat plate as the foundation design to encounter the arise matter by reducing its complication yet easy to manufacture experimentally. In this work, the model output was evaluated by using ANSYS WORKBENCH 2019 software to simulate two-dimensional flow analysis for the rotational velocities of 500 RPM and 1000 RPM, respectively. This was done for different Reynolds numbers ranging from 4.56E+05 to 2.74E+06 which implicitly implied with free stream velocities varying from 5 m/s to 30 m/s for different angles of attack between 0 to 20 degrees. Prior to developing the best model embedment, the mesh independency test was validated with an error of less than 1%. The study resulted in a remarkable trend that was noticeably up to 32% (500 RPM) and 76% (1000 RPM) better in compared to the one without momentum injection. Similarly, the high recovery led to a tremendously lower of 51% (500 RPM) and 99% (1000 RPM), respectively. In sum, these findings generated a stall angle delay of up to 26% (500 RPM) and 78% (1000 RPM) accordingly.

Spiraling light: from donut modes to a Magnus effect analogy

The insight that optical vortex beams carry orbital angular momentum (OAM), which emerged in Leiden about 30 years ago, has since led to an ever expanding range of applications and follow-up studies. This paper starts with a short personal account of how these concepts arose. This is followed by a description of some recent ideas where the coupling of transverse orbital and spin angular momentum (SAM) in tightly focused laser beams produces interesting new effects. The deflection of a focused light beam by an atom in the focus is reminiscent of the Magnus effect known from aerodynamics. Momentum conservation dictates an accompanying light force on the atom, transverse to the optical axis. As a consequence, an atom held in an optical tweezer will be trapped at a small distance of up to λ/2π away from the optical axis, which depends on the spin state of the atom and the magnetic field direction. This opens up new avenues to control the state of motion of atoms in optical tweezers as well as potential applications in quantum gates and interferometry.

Wake Flow Measurements Behind Rotating Smooth Spheres and Baseballs Near Critical Reynolds Numbers

The flow field behind spinning baseballs at two different seam orientations was investigated, and compared with a smooth sphere, to isolate effects of seams on the Magnus effect at Reynolds numbers of 5×104 and 1×105. The rotational speed of the three spheres varied from 0-2400 rpm, which are typical of spin rates imparted to a thrown baseball. These spin rates are represented non-dimensionally as a relative spin rate relating the surface tangential velocity to the freestream velocity, and varied between 0-0.94. Mean velocity profiles, streamline patterns, and power spectral density of the velocity signals were taken using hot-wire anemometry and/or stereoscopic particle image velocimetry in the wake region. The sphere wake orientation changed over a range of relative spin rates, indicating an inverse Magnus effect. Vortex shedding at a Strouhal number of 0.25 was present on the sphere at low relative spin rates. However, the seams on the baseball prevented any consequential change in wake orientation and, at most spin rates, suppressed the shedding frequency exhibited by the sphere. Instead, frequencies corresponding to the seam rotation rates were observed in the wake flow. It was concluded that the so-called inverse Magnus effect recorded by previous investigators at specific combinations of Reynolds number and relative spin rate on a sphere exists for a smooth sphere or an axisymmetrically dimpled sphere but not for a baseball near critical Reynolds numbers, where the wake flow pattern is strongly influenced by the raised seams.

Evaluation of Magnus Force on Check Ball Behavior in a Hydraulic L Shaped Pipe

This paper presents the effect of the rotational speed of a check ball in a hydraulic L-tube on the translational motion caused by the Magnus effect. A spring-driven ball check valve is one of the most important components of a hydraulic system and controls the position of the ball to prevent backflow. To simplify the structure, the springs must be eliminated. To this end, it is necessary to clarify the flow pattern of the check ball in an L-shaped pipe and the rotational and translational behaviors of the ball. In this study, the position of the inlet pipe and the availability of the check were determined using Computer Aided Engineering (CAE) tools. By moving the position of the inlet pipe from the top to the bottom of the housing, the direction of the rotation of the ball was reversed, and the behavior changed significantly. It was found that the Magnus force, which causes the ball to levitate by rotating it in the opposite direction to the flow, acts to shorten the floating time.

Effects of spin rate on the surface pressure distribution of a rotating model

A new experimental technique has been developed to measure the pressure distribution over the surface of a rotating model in a wind tunnel for various spin rates, free-stream Mach numbers, and angles of attack. In this method, all of the measuring instruments are placed inside the rotating model which eliminated previous operational limitations and technical problems associated with attempts to measure the Magnus effect. The validity and reliability of the measured data was verified by comparing the integrated surface pressure values and aerodynamic forces, with those directly measured from an internal strain gauge balance. From the acquired surface pressure data distribution of both local and total Magnus force on the model as well as the interpretation of the boundary layer and flow separation effects on the rotating model could be determined. The Magnus force distribution shows that the local Magnus force increases along the length of the model and the maximum local Magnus force occurs at the end of the projectile. The acquired experimental data were further compared with the numerical simulations and satisfactory results were achieved. This new experimental technique can be easily applied to a variety of model configurations testing at different Mach numbers, spin rates, angles of attack, etc.