Wind tunnel measurement gives the velocity field and vorticity field in intersectionplane at different downstream position, which is up to 20 times cord-length.
风洞实验采用PIV测量了沿流向下游不同截面的涡量场和速度场，测量截面距机翼后缘最远达到20倍弦长。
2
So, remember, in the linear system, you can think of a linear system as asking you to find the intersection between three planes because each equation is the equation of a plane.
记住，线性方程组问题，可以理解为求三个平面的交，因为每个方程就是一个平面。
3
Say that I give you an ellipse in space as maybe the more, well, one exciting way to parameterize an ellipse in space is maybe the intersection of a cylinder with a slanted plane.