cases:case019

Fig. 1: Flow geometry and test section

The boundary layer develops over the inner wall of an annular pipe of diameter 200 mm. As shown in figure 1, the streamwise pressure gradient is generated by suction of air through a perforated section of the concentric inner tube of the annulus. This inner tube is of diameter 80 mm, and can be moved in the axial direction, so that its distance from the measurement section at $x_M$ can be varied. $x_A$ denotes the distance of this porous section upstream of the measurement location (negative values for $x_A$ indicate cases where the porous section was located downstream of $x_M$).

The measurement location $x_M$ is 675 mm downstream of the straight pipe inlet. Measurements of the boundary layer are also provided at $x_E$ (400 mm upstream of $x_M$), and these could be used as inlet conditions for most cases.

Results are reported for two different suction conditions (AG1 and AG2) and for different values of the dynamic pressure $q_D=P_o - P_D$, as listed in the table below. In each case, a number of positions of the perforated section, $x_A$, are considered.

 AG1 $q_D$ [Pa] 1000 - 1000 600

Velocity measured using Pitot tube.

Velocity and turbulence statistics measured with hot wire.

Data available include:

• Wall pressure and shear stress measurements
• Mean velocity profiles across and along the pipe for various $x_A$ locations

Sample plots of selected quantities are available.

Boundary layer measurements at Section $x_E$ (for both $q_D=600$ and $1000$ Pa cases)

File Description
e_hw.dat Hot-wire mean velocity and Reynolds stress profiles
e_pi.dat Pitot tube mean velocity profiles
e_tauw.dat Circumferential distribution of wall shear stress

Measurements at Section $x_M$

Hot-wire mean velocity and Reynolds stress profiles
m_hw_1.dat Case AG1/1000, for $x_A=-100$, $0$, $50$, $100$, $200$, $300$ mm
m_hw_2.dat Case AG2/1000, for $x_A=-100$, $0$, $50$, $100$, $200$, $300$ mm
m_hw_3.dat Case AG2/600, for $x_A=-100$, $50$, $100$, $300$ mm
Pitot tube mean velocity profiles
m_pi_1.dat Case AG1/1000, for $x_A=-100$, $0$, $50$, $100$, $200$, $300$ mm
m_pi_2.dat Case AG2/1000, for $x_A=-100$, $0$, $50$, $100$, $200$, $300$ mm
m_pi_3.dat Case AG2/600, for $x_A=-100$, $50$, $100$, $300$ mm
Wall shear stress measurements
m_tauw.dat Measurements for all three cases, with $x_A$ ranging from $-100$ to $400$ mm
m_tauw_p.dat Measurements with wall pulsed-wire for case AG2/600, for $x_A$ ranging from $20$ to $400$ mm

Pressure measurements along the pipe

Pressure distribution along the pipe wall, from $x=230$ to $715$ mm
r_pres_1.dat Case AG1/1000, for $x_A$ ranging from $-100$ to $400$ mm
r_pres_2.dat Case AG2/1000, for $x_A$ ranging from $-100$ to $400$ mm
r_pres_3.dat Case AG2/600, for $x_A$ ranging from $-100$ to $400$ mm

Velocity measurements along the pipe

Mean velocity distribution along selected sections of the pipe
r_v_30_1.dat Case AG1/1000, at $y=30$ mm, for $x_A$ ranging from $-75$ to $300$ mm
r_v_30_2.dat Case AG2/1000, at $y=30$ mm, for $x_A$ ranging from $-75$ to $300$ mm
r_v_40_1.dat Case AG1/1000, at $y=40$ mm, for $x_A$ ranging from $-75$ to $300$ mm
r_v_40_2.dat Case AG2/1000, at $y=40$ mm, for $x_A$ ranging from $-75$ to $300$ mm
r_v_40_3.dat Case AG2/600, at $y=40$ mm, for $x_A$ ranging from $-75$ to $300$ mm
1. Gasser, D. (1992). Experimentelle Untersuchung stark verzoegerter turbulenter Grenzschichten. PhD Thesis, Swiss Federal Institute of Technology (ETH), Zurich, Switzerland.
2. Hirt, F., Thomann, H. (1986). Measurement of wall shear stress in turbulent boundary layers subject to strong pressure gradients. J. Fluid Mech., Vol. 171, pp. 547-562.

Indexed data:

case019 (dbcase, semi_confined_flow)
case019