# Geometry

The orgininal geometry was based on a conceptual design of a long haul small commercial jet with intended cruise Mach number of 0.87. For CFD validation purposes it was recognized that wing deformation may not be excessive. In order to reduce the deformation of the wind tunnel model under loading, the wing was re-designed at a reduced Mach number of 0.85 and the wing thickness was increased. The resulting geometry was defined as the CAE–AVM (Chinese Aeronautical Establishment - Aerodynamic Validation Model).

The CAE-AVM represents a small transonic transport configuration designed to fly at a cruise Mach number of M=0.85 with a nominal lift condition of CL=0.50, at a flight Reynolds number of Re=20 million. To match with experimental wind tunnel data all comparisons are made based on a model chord Reynolds number of Re=4.7 million.

Geometry:

Geometry:

Two types of geometry will be made available (in STEP file format) for the workshop:

**CAE-AVM**: Full airplane configuration with nominal design shape.**CAE-AVM-DZ**: Full airplane configuration with sting and deformed wing shape (as acquired at test status of M=0.85 / Re=4.7 million / CL=0.515).

*Definitions and axes systems:*

The models are defined in structural coordinate system. The origin point of this system is on the fuselage axis and located at the starting section of the cylindrical portion of the fuselage. The station direction is X_{c}-axis, from nose to tail. The buttock line direction is Y_{c}, from left to right. The water line direction is Z_{c}-axis, from bottom to top, as shown in the figure below.

The reference point for the moments is X_{c}=0.4954 m, Y_{c}=0 m, Z_{c}=0 m, defined in the structural coordinate system. The reference length is 0.1988 m, which is the mean aerodynamic chord of the wing. The reference area is the total area of the wing, 0.2075 m². The full span is 1.372 m.

Wind coordinate system and body coordinate system is defined in the figure. The body coordinate system (X, Y, Z in the figure) is similar to structural coordinate system, but its origin is located at the moments reference point. Its direction of X-axis points forward (upstream), and Z-axis points downward. The wind coordinate system (X_{a}, Y_{a}, Z_{a} in the figure) is similar to body coordinate system, but its direction of X_{a}-axis points the direction of flight. Its direction of Y_{a}-axis coincidences with body coordinate system because of the angle of side slip is zero in the figure. The included angle between X-axis and X_{a}-axis is the angle of attack.

The model geometry can be downloaded from the Data Transfer page.