in this study, the effects of linear and rotational speed of the friction stir welding tool was investigated on the heat generation and distribution at surface and inside of workpiece, material flow and geometry of the welding area of poly methyl methacrylate (pmma) workpiece. the commercial cfd fluent 6.4 software was used to simulation of the process with computational fluid dynamic technique...

This study presents a new approach for evaluation of oil-film pressure in hydrodynamic bearing. Oil-film pressure is one of the critical parameter which determines the performance of hydrodynamic bearing. In this research parameters of rotational speed, bearing load and oil-feed pressure are considered as model independent variables. Modelling and simulations are done in Matlab. The research sh...

Automatic balancing devices, comprising several balls in circular tracks, can efficiently compensate rigid rotor unbalance within certain ranges of rotational speed. However, near critical speeds the vibration level can be comparatively high due to the phenomenon, which is similar, but not identical to the well-known Sommerfeld-effect in unbalanced rotors with a limited driving moment. The pres...

In this research, the effects of parameters include tool rotational and traverse speeds were investigated on heat generation and material flow during friction stir welding of Ti-6Al-4V alloy with computational fluid dynamics (CFD) method. Simulation results showed that with increasing of tool rotational and decreasing tool traverse speed, the more frictional heat generates which causes formatio...

We demonstrate a computationally efficient method for correcting the nonuniform rotational distortion (NURD) in catheter-based imaging systems to improve endoscopic en face optical coherence tomography (OCT) and OCT angiography. The method performs nonrigid registration using fiducial markers on the catheter to correct rotational speed variations. Algorithm performance is investigated with an u...