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1.1.4. Computational method
Computational method strongly depends on the way of aircraft body modeling. The model
defined in chapter 1.1.3 concerns only flow and doesn’t define the object. Generally two methods are in
use. In the first method the body of aircraft is modeled using thin surfaces. The second method uses
three dimensional model of the aircraft body. PANUKL 2002 package bases on the low order panel
method, where the Dirichlet problem is solved (Hess method [7]). The quadrangle panels are used. The
flat vortex wake, parallel to the free stream velocity or parallel to chord is assumed.
The base of the method is solution of the Laplace equation for the full velocity potential.
The velocity potential can be written in form [6]:
1
1
1
4
n
r 4
2
0;
(7)
x, y,
z
dS
dS
BODY WAKE
Assuming the following boundary conditions:
- internal Dirichlet boundary condition on the body surface:
where:
1
4
BODY
1
1
dS
n
r 4
WAKE BODY
BODY
1
r
1
dS 0
r
doublet strength: = - ( - i ), (10)
source strength: = /n. (11)
- Kutta-Joukowsky conditions on the trailing edge:
- on the vortex wake:
p( x,
y)
TE 0 (12)
(
x,
y)
0;
x
(8)
(9)
(13)
6