One Machi Going Up, Upside Down

Wait a minute... if,

\(r=a+bcos(\theta)\)   and     \(a<0\),  \(|a|>b>0\)

then the curve should be upside down,

The tube should lift this way up where the upside \(\frac{v^2}{r}\) has a higher value as \(r\) is smaller, \(v\) being constant throughout the tube.