2005年7月18日 · 1) I think the 2nd formula should be: Cl = Cl alpha*AR/(AR+2)*(alpha + alpha0) instead of Cl = Cl alpha*(AR/AR+2)*(alpha + alpha0) which will reduce into formula 1 when AR -> infinity. 2) when the AoA is too big, the leading edge vortex will depart from the wing backside, which is called stall - no more lift, not as much drag as well.

2012年3月9日 · I am currently trying to calculate 3D CL values to compare with my 2D xfoil data. I understand that the 3D values will have a lower CLmax (~90%) with a stall alpha which is higher. I have a dCl/dalpha for my 2D of 0.1132 (per degree) and Clmax of 1.667. But require a 3D CL-alpha plot. How can I...

2002年12月12日 · You are probably thinking about Cl_alpha which is just the slope of the Cl vs alpha plot..classical 2d linear potential flow theory give this as 2*pi for a 2d airfoil..for a 3d wing you have to modify it somewhat to take into account Aspect ratio and sweep. R.T Jones

2008年12月16日 · a reasonable estimate is for -18<AoA<18deg, CL = 2pi*sin(AoA0 and zero elsewhere. separation isn't exactly at 18deg, varies with reynolds number (researching this specifically'll probably get you some useful results), post-separation lift isn't exactly zero, pre-reattachment lift isn't exactly zero.

2003年8月28日 · I also know from Lifting Line theory that Cd=Cdmin +(CL^2/pi x AR x e--Oswald's efficiency factor), but you see that that formula doesn't make any use of the 2D value for Cd from the charts--the only thing it relates to again is the CL vs alpha slope.

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2022年5月6日 · I wanted to know if there is a way to get those coefficient in sol146 without using matrix QHHL. Thanks!

2003年6月4日 · where alpha=n-1. The coulombic attraction in an ionic bond is a long range interaction that varies as 1/r. Because of this, an Na+ ion not only interacts attractively with its neighboring Cl- ions, but it also interacts repulsively with its slightly more distant Na+ neighbors.

2005年4月24日 · As suggested before, for fire rating, you have to judge from the function of the element you are evaluating. A column is a single element for which failure can trigger a series of adjacent elements to follow suite, and likely resulting in structural collapse over a significant areas, if not the complete building/structure, and render the building/structure un-inhabitable.

2002年12月12日 · We ae fabricating a vessel where in the shell and the head material is to be SA 516 Gr 70 N 1/2" thk. The heads are to be hot formed . The head manufacturer does not have SA 516 Gr 70 plate in Normalized condition. What he proposes is thta if the heads are hot formed in the normalizing range...