Merge branch 'fix/aerodynamic_analysis' into 'develop'

aerodynamic_analysis (schueltke): added lili documentation

See merge request !50

docs/documentation/analysis/aerodynamic_analysis/aerodynamic_principles.md

@@ -47,10 +47,10 @@ For this purpose, the potential equations are used, i.e. the flow is simplified
 The wing is reduced to its skeletal lines.
 This simplified geometry is divided into trapezoidal elementary wings, which are covered with free and bound vortices.
 A system of equations is constructed from the vortex system and the boundary conditions, the solution of which is used to calculate the lift distribution.
-For a more in-depth discussion, the  dissertation by Horstmann (Horstmann 1987: Ein Mehrfach-Traglinienverfahren und seine Verwendung für Entwurf und Nachrechnung nichtplanarer Flügelanordnungen) is recommended.
+For a more in-depth discussion, the  dissertation by Horstmann [Horstmann 1987: Ein Mehrfach-Traglinienverfahren und seine Verwendung für Entwurf und Nachrechnung nichtplanarer Flügelanordnungen](references/Horstmann_1987_Mehrfachtraglinienverfahren.pdf) is recommended or the [user-documentation of Lifting Line](references/LIFTING_LINE_V3.2_UserDoc.pdf).
 
-The following picture shows the lifitng surfaces of a typical TAW aircraft discretized into elementary wings according to the lifting line method:
-![A wing and horizontal tailplane broken down into elementary wings](img/ll_geom.png)
+The following picture shows the lifting surfaces of a typical TAW aircraft discretized into elementary wings according to the lifting line method:
+![A wing and horizontal tailplane broken down into elementary wings](figures/ll_geom.png)
 
 The Prandtl-Glauert transformation is applied to the polars from Lifting Line.
 Lift coefficients, induced drag and pitch moment coefficients are thus transformed to include the compressibility effects.
@@ -87,7 +87,7 @@ From flight data it could be deduced that with increasing Mach number the wave d
 This behavior of the wave drag is approximated by a fourth degree polynomial.
 
 The following picture shows the drag creep in the flight test data of a DC-9-30, according to Gur, Full-COnfiguration Drag Estimation, 2010:
-![The rise of the wave drag for a typical aircraft](img/Drag_creep.png)
+![The rise of the wave drag for a typical aircraft](figures/Drag_creep.png)
 
 To calculate the wave drag, the critical Mach number is required, which is calculated according to the Korn-Mason equation (Mason 1990: Analytic Models for Technology Integration in Arcraft Design).
 To calculate the critical Mach number, the wing sweep, the profile thickness ratio, the local lift coefficient and the "profile technology factor" are required.
@@ -120,4 +120,4 @@ For this, the number, type, postions and areas of all leading and trailing edge
 The geometric parameters of the high lift devices are used to calculate a maximum lift coefficient and shifts of the drag and moment coefficients, based on a set of semi-empirical formulas.
 
 The following picture shows the shifts in lift and drag in the high lift polars for a typical short medium range passernger aircraft according to the method:
-![An example of a clean polar and transformed high lift polars at Mach 0.2](img/high_lift_shift.png)
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+![An example of a clean polar and transformed high lift polars at Mach 0.2](figures/high_lift_shift.png)
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