worked on diff requests

docs/documentation/analysis/aerodynamic_analysis/aerodynamic_principles.md

@@ -34,7 +34,7 @@ The methods shown above have certain limitations:
 - The methods are only valid for certain flight conditions and aircraft configurations
 - Most methods need other aerodynamic values as input for their calculation
   
-Because of these shortcommings, the engineer has to select a suitable set of methods for his aircraft and bundle them together into a **strategy**.
+Because of these shortcommings, the engineer has to select a suitable set of methods for their aircraft and bundle them together into a **strategy**.
 Due to the complexitiy in the fields of aerodynamics, the individual methods cannot be pluged in and out of a strategy, rather the strategies are tailor made for a given case.
 For illustration, the default strategy for calculation of the polars for the TAW is explained in the next chapter.
 
@@ -55,7 +55,7 @@ The following picture shows the lifitng surfaces of a typical TAW aircraft discr
 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.
 The lift distribution calculated using lifting line agrees well with CFD results for both the conventional wing and the blended wing body.
-The calculated induced drag cannot be validated by CFD methods.
+Since the concept of the induced drag is based on the lifting line theory, it cannot be validated by CFD methods, which are based on the Navier-Stokes-Equations.
 Several semi-empirical corrections are integrated into the lifting line methodology in UNICADO.
 Based on Roskam, induced drag is calculated for the fuselage and nacelles.
 The pitching moment is corrected for fuselage and nacelle influences based on Torenbeek (Torenbeek, E. - Advanced Aircraft Design, 2013, ISBN: 9781119969303).
@@ -76,7 +76,7 @@ The friction coefficient is derived from the flow around a flat plate and depend
 In addition to the drags for the individual components, a 'miscellaneous drag' is calculated.
 This includes resistance caused by gas entering and leaving the hull through leaks and resistance caused by antennas, protrusions and the like.
 In total, the viscous drag depends only on the geometry, Reynolds number and Mach number and is thus constant over an entire aircraft polar.
-But a calibration method is built in which the viscous drag is calibrated using an exponential function based on the lift coefficient.
+A calibration method is built in which the viscous drag is calibrated using an exponential function based on the lift coefficient.
 Thus, the viscous drag slightly increases with increasing lift.
 
 ### Wave drag according to Mason

docs/documentation/analysis/aerodynamic_analysis/software_architecture.md

 # Software architecture {#softwarearchitecture}
 
-The software architecture is structured into various modules and packages, each handling specific task. Below is a description of the main components
+The software architecture is structured into various modules and packages, each handling specific tasks. Below is a description of the main components
 
 - strategies:
   - **Strategies** define the procedure of calculating the polars by initializing the aircraft geometry, calling methods and copying and processing data.