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D. Subramanian et al.
altitudes and flight speeds and is usually hand-launched. The design of MAVs is
difficult due to a lack of exhaustive understanding of the aerodynamics pertaining
to small vehicles. Also, due to the low endurance, which is often of the order of
few minutes, design modifications are required in order to achieve high aerodynamic
efficiencies. Mueller et al. [2] had conducted a thorough study on the lift, drag and
pitching moment characteristics of low aspect ratio wings in low Reynolds number
flows. They focused on the effects of aspect ratio and wing planform on moments
and forces in low Reynolds number flows and they provide the experimental data of
lift, drag and moment for Zimmerman planforms of various aspect ratios. Moreover,
the Zimmerman planform is one among many MAV planforms which was proposed
for real-time flight [2].
The manta ray (Manta birostis) is a giant ray found in temperate, subtropical and
tropical waters and have been found to weigh as much as 3 tonnes [3]. Mantas propel
through water by moving their pectoral fins in a wing-like fashion, which drives water
backwards. The oscillatory swimming strokes of the manta ray have been studied by
Fish et al. [4]. Wang et al. [5] studied the hydrodynamic performance of a manta rayinspired underwater glider which displayed significant improvements in lift-to-drag
ratios compared to a conventional underwater glider. However, manta ray-inspired
designs have seldom been researched for applications in MAVs.
The current effort is focused on improving the aerodynamic characteristics of
the base Zimmerman planform by providing bio-inspired modifications, thereby
allowing it to be used for a wider range of applications.
2 Geometric Modelling
The baseline wing planform was decided to be the Zimmerman planform model
with an aspect ratio of 1 as it was suitable for low aspect ratio MAVs. A Zimmerman
planform is a combination of two ellipses that have a common axis length in which
the upper ellipse’s major axis coincides with the lower ellipse’s minor axis as shown
in Fig. 1a. The Zimmerman planform was chosen as it has been experimentally shown
to have high C Lmax and displays favourable post-stall behaviour which allows them
operate at a wider range of angles of attack [6]. Drawing inspiration from manta rays
and extensions were superimposed on the planform by taking reference from the
curved pattern of the manta ray. The Manta A and Manta B planforms were created
by providing extensions to the existing Zimmerman planform using Bezier curve as
shown in Fig. 1b.
3 Computational Domain and Validation
A half-wing model enclosed in a half cylinder is used as the computational domain as
shown in Fig. 2a, which minimize the mesh and the computation time. The length and
D. Subramanian et al.
altitudes and flight speeds and is usually hand-launched. The design of MAVs is
difficult due to a lack of exhaustive understanding of the aerodynamics pertaining
to small vehicles. Also, due to the low endurance, which is often of the order of
few minutes, design modifications are required in order to achieve high aerodynamic
efficiencies. Mueller et al. [2] had conducted a thorough study on the lift, drag and
pitching moment characteristics of low aspect ratio wings in low Reynolds number
flows. They focused on the effects of aspect ratio and wing planform on moments
and forces in low Reynolds number flows and they provide the experimental data of
lift, drag and moment for Zimmerman planforms of various aspect ratios. Moreover,
the Zimmerman planform is one among many MAV planforms which was proposed
for real-time flight [2].
The manta ray (Manta birostis) is a giant ray found in temperate, subtropical and
tropical waters and have been found to weigh as much as 3 tonnes [3]. Mantas propel
through water by moving their pectoral fins in a wing-like fashion, which drives water
backwards. The oscillatory swimming strokes of the manta ray have been studied by
Fish et al. [4]. Wang et al. [5] studied the hydrodynamic performance of a manta rayinspired underwater glider which displayed significant improvements in lift-to-drag
ratios compared to a conventional underwater glider. However, manta ray-inspired
designs have seldom been researched for applications in MAVs.
The current effort is focused on improving the aerodynamic characteristics of
the base Zimmerman planform by providing bio-inspired modifications, thereby
allowing it to be used for a wider range of applications.
2 Geometric Modelling
The baseline wing planform was decided to be the Zimmerman planform model
with an aspect ratio of 1 as it was suitable for low aspect ratio MAVs. A Zimmerman
planform is a combination of two ellipses that have a common axis length in which
the upper ellipse’s major axis coincides with the lower ellipse’s minor axis as shown
in Fig. 1a. The Zimmerman planform was chosen as it has been experimentally shown
to have high C Lmax and displays favourable post-stall behaviour which allows them
operate at a wider range of angles of attack [6]. Drawing inspiration from manta rays
and extensions were superimposed on the planform by taking reference from the
curved pattern of the manta ray. The Manta A and Manta B planforms were created
by providing extensions to the existing Zimmerman planform using Bezier curve as
shown in Fig. 1b.
3 Computational Domain and Validation
A half-wing model enclosed in a half cylinder is used as the computational domain as
shown in Fig. 2a, which minimize the mesh and the computation time. The length and