Numerical Modeling and Analysis of a Multi-rotor UAS
175
Fig. 4 Mesh quality a skewness and b orthogonality
boundary condition and the other four faces are given “wall” boundary conditions
for simulating the flow field. It is observed that there is a recirculating flow that helps
the quadcopter stay horizontal/flat. Figure 5 shows the flow field for zero degrees
angle of attack.
Similar flow fields with varying peak pressures and maximum velocities are
observed for other angles of attack which are summarized in Table 1. It may be
observed that the maximum velocity in the MRF region decreases initially and
then increases. Since the parameters like density and free stream velocities remain
constant, the best angle of attack lies in between 4° and 8°.
Fig. 5 Pressure and velocity flow fields in the MRF region (hovering)
Table 1 Maximum pressure and velocities for different angles of attack (hovering)
Angles of attack (°)
Max. pressure (Pa)
Propeller tip velocity (m/s)
0
101,333
5.133
4
101,335
5.109
8
101,334
5.190
12
101,340
6.148
175
Fig. 4 Mesh quality a skewness and b orthogonality
boundary condition and the other four faces are given “wall” boundary conditions
for simulating the flow field. It is observed that there is a recirculating flow that helps
the quadcopter stay horizontal/flat. Figure 5 shows the flow field for zero degrees
angle of attack.
Similar flow fields with varying peak pressures and maximum velocities are
observed for other angles of attack which are summarized in Table 1. It may be
observed that the maximum velocity in the MRF region decreases initially and
then increases. Since the parameters like density and free stream velocities remain
constant, the best angle of attack lies in between 4° and 8°.
Fig. 5 Pressure and velocity flow fields in the MRF region (hovering)
Table 1 Maximum pressure and velocities for different angles of attack (hovering)
Angles of attack (°)
Max. pressure (Pa)
Propeller tip velocity (m/s)
0
101,333
5.133
4
101,335
5.109
8
101,334
5.190
12
101,340
6.148