Page 317 - Computational Fluid Dynamics for Engineers

10.5 Model Problem for the Transonic Small Disturbance Equation 307

1
K=2.5 K=2.1
error)
2 0
CD
H
£
o Log (potential \
o> -1 -\
o

i i i i ~~"i i i i i i
2500 5000
Iterations Iterations

K=1.8 K=1.15
2 2
* ° CD
c
a> 0)
o O
Q.
o O
^ tu

2500 5000 2500 5000
Iterations Iterations
Fig. 10.9. Convergence of the residuals of <p on circular arc airfoil with TSD theory.

co=0.5
CO=1.5
co=1.9

CD

o
Q.
o

Fig. 10.10. Effect of relaxation factor u;
Iterations on convergence rate.

numbers (lower K). The presence of spikes on the curve is due to the discon-
tinuous switch from elliptic to hyperbolic difference operators in the supersonic
region. The convergence rate variation as a function of the relaxation factor UJ