In case of turbulent flow of fluid through a circular pipe, the

• A. mean flow velocity is about 0.5 times the maximum velocity.
• B. velocity profile becomes flatter and flatter with increasing Reynolds number.
• C. point of maximum instability exists at a distance of 2r/3 from the pipe wall (r = pipe radius).
• D. skin friction drag, shear stresses, random orientation of fluid particles and slope of velocity profile at the wall are more.