發送短信 : Visualization of counter-rotating streamwise vortices in a rectangular channel with one-sided wavy surface

   _____     ___      _  __   _    _      _____  
  / ___//   / _ \\   | |/ // | || | ||   / ___// 
  \___ \\  | / \ ||  | ' //  | || | ||   \___ \\ 
  /    //  | \_/ ||  | . \\  | \\_/ ||   /    // 
 /____//    \___//   |_|\_\\  \____//   /____//  
`-----`     `---`    `-` --`   `---`   `-----`