Yawed cylinders

Beckwith, I.E. and Gallagher J.J., Local Heat Transfer and Recovery Temperatures on a Yawed Cylinder at a Mach Number of 4.15 and High Reynolds Numbers , NASA TR-R-104, 1962. 

Poll, D.I.A. (1985) Some observations of the transition process on the windward face of a long yawed cylinder. J. Fluid Mech., 150, 329-356. 

FIGURE 6.18 Sketch of coordinates employed for related two-dimensional flows, (a) axisymmetric body (6) yawed cylinder of infinite length. 

Exact similar solutions are possible for stagnation regions where ue 0 and te is a constant and equal to unity for an axisymmetric body and to i, for a yawed cylinder. The terms involving te drop out of Eqs. 6.100-6.102, and similarity occurs for constant i and ftp. 

In a stagnation region, the fluid properties are nearly constant, and ue x also r = x. Thus, = Vi for an axisymmetric body, and Pp = 1 for a yawed cylinder. 

FIGURE 6.25 The effect of surface mass transfer on the recovery factor on the stagnation line of a yawed cylinder of infinite length [48],... 

I. E. Beckwith, Similar Solutions for the Compressible Boundary Layer on a Yawed Cylinder With Transpiration Cooling, NASA Tech. Rep. R-42, 1959. 

In reality, the nodes move as well, but with a distance factor to the turning of the cylinder. This distance factor is called the Bryan factor. The moving of the nodes can be detected and is a measure for the yaw rate. This principle, when produced by precision mechanics, gives an excellent resolution (about 0.01 °/s) and is used in the aircraft industry. The following yaw-rate sensor for automotive application works on this basis (Fig. 7.2.17). 

They operate as drive, amplitude control of the drive, detectors for the oscillation nodes, and as actuators to keep the nodes in place. The principle enables a complete self-test by simulating a yaw rate via the piezoactuators of the closed loop. A yaw-rate sensor based on the principle of a vibrating cylinder is used in VDC systems (Fig. 7.2.18). This principle has been used in a similar way in silicon micromachining and is used in a yaw-rate sensor for VDC [9]. 

The yaw angle A is the complement of the angle between the free-stream direction and the cylinder axis (see Fig. 6.18). 

Kuethe, A.M. (1951). Some aspects of boundary-layer transition and flow separation on cylinders in yaw. Prof F Midwestern Conference on Fluid dynamics 1 44-55. 

To use eq. 6.2.9 to get the true shear rate, we must have additional data near the point of interest Furthermore, numerical differentiation of data is notoriously inaccurate. Fortunately, this correction does not greatly alter the shtqw of the viscosity versus shear rate function. The apparent (Newtonian) shear rate Yaw is multiplied by (3 -I-1 /n )/4 and the viscosity is divided by it Thus data points are shifted to the right and down along a line with slope —I on a log-log plot as illustrated in Figure 6.2.2. The correction is similar to that for a wide gap concentric cylinders rheometer (Figure 5.3.2). 

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