Results from large eddy simulations (LES) of fully developed flow in a 90 deg ribbed duct are presented with rib pitch-to-height ratio $P/e=10$ and a rib height-to-hydraulic-diameter ratio $e/Dh=0.1.$ Three rotation numbers $Ro=0.18,$ 0.36, and 0.68 are studied at a nominal Reynolds number based on bulk velocity of 20 000. Centrifugal buoyancy effects are included at two Richardson numbers of Ri=12, 28 (Buoyancy parameter, $Bo=0.12$ and 0.30) for each rotation case. Heat transfer augmentation on the trailing side of the duct due to the action of Coriolis forces alone asymptotes to a value of 3.7±5% by Ro=0.2. On the other hand, augmentation ratios on the leading surface keep decreasing with an increase in rotation number with values ranging from 1.7 at Ro=0.18 to 1.2 at Ro=0.67. Secondary flow cells augment the heat transfer coefficient on the smooth walls by 20% to 30% over a stationary duct. Centrifugal buoyancy further strengthens the secondary flow cells in the duct cross-section which leads to an additional increase of 10% to 15%. Buoyancy also accentuates the augmentation of turbulence near the trailing wall of the duct and increases the heat transfer augmentation ratio 10% to 20% over the action of Coriolis forces alone. However, it does not have any significant effect at the leading side of the duct. The overall effect of buoyancy on heat transfer augmentation for the ribbed duct is found to be less than 10% over the effect of Coriolis forces alone. Friction on the other hand is augmented 15% to 20% at the highest buoyancy number studied. Comparison with available experiments in the literature show excellent agreement.

1.
Smagorinsky
,
J.
,
1963
, “
General Circulation Experiments With the Primitive Equations. I. The Basic Experiment
,”
Monthly Weather Review
,
91
, pp.
99
164
.
2.
Germano
,
M.
,
Piomelli
,
U.
,
Moin
,
P.
, and
Cabot
,
W. H.
,
1991
, “
A Dynamic Subgrid-Scale Eddy Viscosity Model
,”
Phys. Fluids A
,
3
, pp.
1760
1765
.
3.
Watanabe, K., and Takahashi, T., 2002, “LES Simulation and Experimental Measurement of Fully Developed Ribbed Channel Flow and Heat Transfer,” ASME Paper No. 2002-GT-30203.
4.
Murata
,
A.
, and
Mochizuki
,
S.
,
1999
, “
Effect of Cross-Sectional Aspect Ratio on Turbulent Heat Transfer in an Orthogonally Rotating Rectangular Smooth Duct
,”
Int. J. Heat Mass Transfer
,
42
, pp.
3803
3814
.
5.
Murata
,
A.
, and
Mochizuki
,
S.
,
2000
, “
Large, Eddy Simulation With a Dynamic Subgrid-Scale Model of Turbulent Heat Transfer in an Orthogonally Rotating Rectangular Duct With Transverse Rib Turbulators
,”
Int. J. Heat Mass Transfer
,
43
, pp.
1243
1259
.
6.
Murata
,
A.
, and
Mochizuki
,
S.
,
2001
, “
Comparison Between Laminar and Turbulent Heat Transfer in a Stationary Square Duct With Transverse or Angled Rib Turbulators
,”
Int. J. Heat Mass Transfer
,
44
, pp.
1127
1141
.
7.
Iacovides
,
H.
, and
Launder
,
B. E.
,
1991
, “
Parametric and Numerical Study of Fully Developed Flow and Heat Transfer in Rotating Rectangular Ducts
,”
ASME J. Turbomach.
,
133
, pp.
331
338
.
8.
Bo
,
T.
,
Iacovides
,
H.
, and
Launder
,
B. E.
,
1995
, “
Developing Buoyancy-Modified Turbulent Flow in Ducts Rotating in Orthogonal Mode
,”
ASME J. Turbomach.
,
177
, pp.
474
484
.
9.
Prakash
,
C.
, and
Zerkle
,
R.
,
1992
, “
Prediction of Turbulent Flow and Heat Transfer in a Rotating Square Duct
,”
ASME J. Turbomach.
,
114
, pp.
835
846
.
10.
Prakash
,
C.
, and
Zerkle
,
R.
,
1995
, “
Prediction of Turbulent Flow and Heat Transfer in a Ribbed Rectangular Duct With and Without Rotation
,”
ASME J. Turbomach.
,
117
, pp.
255
264
.
11.
Ooi
,
A.
,
Iaccarino
,
G.
,
Durbin
,
P. A.
, and
Behnia
,
M.
,
2002
, “
Reynolds Averaged Simulation of Flow and Heat Transfer in Ribbed Ducts
,”
Int. J. Heat Fluid Flow
,
23
, pp.
750
757
.
12.
Saidi
,
A.
, and
Sunden
,
B.
,
2001
, “
On Prediction of Thermal-Hydraulic Characteristics of Square-Sectioned Ribbed Cooling Ducts
,”
ASME J. Turbomach.
,
123
, pp.
614
620
.
13.
Parsons
,
J. A.
,
Han
,
J. C.
, and
Zang
,
Y. M.
,
1994
, “
Wall Heating Effect on Local Heat Transfer in a Rotating Two-Pass Square Channel With 90° Rib Turbulators
,”
Int. J. Heat Mass Transfer
,
37
, pp.
1411
1420
.
14.
,
S. V.
, and
Han
,
J. C.
,
1997
, “
Detailed Heat Transfer Distributions in Two-Pass Square Channels With Rib Turbulators
,”
Int. J. Heat Mass Transfer
,
40
, pp.
2525
2537
.
15.
Wagner
,
J. H.
,
Johnson
,
B. V.
,
Graziani
,
R. A.
, and
Yeh
,
F. C.
,
1992
, “
Heat Transfer in Rotating Serpentine Passages With Trips Normal to the Flow
,”
ASME J. Turbomach.
,
114
, pp.
847
857
.
16.
Liou, T. M., Chen, M. Y., and Tsai, M. H., 2001, “Fluid Flow and Heat Transfer in a Rotating Two-Pass Square Duct With In-Line 90° Ribs,” ASME Paper No. 2001-GT-0185.
17.
Abdel-Wahab, S., and Tafti, D. K., 2004, “Large Eddy Simulation of Flow and Heat Transfer in a 90° Ribbed Duct With Rotation—Effect of Coriolis Forces,” ASME Paper No. 2004-GT-53796.
18.
Tafti, D. K., 2001, “GENIDLEST—A Scalable Parallel Computational Tool for Simulating Complex Turbulent Flows,” Proceedings ASME Fluids Engineering Division, FED—Vol. 256, ASME-IMECE, New York.
19.
Tafti, D. K., 2004, “Evaluating the Role of Subgrid Stress Modeling in a Ribbed Duct for the Internal Cooling of Turbine Blades,” Intl. J. Heat Fluid Flow, in press.
20.
Incropera, F. P., and Dewitt, D. P., 2002, Fundamentals of Heat and Mass Transfer, 5th ed., Wiley, New York.
21.
Johnston
,
J. P.
,
Halleen
,
R. M.
, and
Lezius
,
D. K.
,
1972
, “
Effects of Spanwise Rotation on the Structure of Two-Dimensional Fully Developed Turbulent Channel Flow.
J. Fluid Mech.
,
56
, pp.
533
557
.