Innovation Grant
Building the Capacity to Incorporate
Authentic Practice in the Delivery of
Engineering Units
Project Report
School of Engineering and IT
Daria Surovtseva
Mirjam Jonkman
Background
The new generation of engineers are expected to be able to conceive-design-implementoperate complex value-added engineering systems in a modern team-based environment
(Crawley et al, 2007). It has been shown by many that the traditional lecture-based
environment does not always provide a suitable framework to address this requirement. On
the other hand, Project Based Learning (PBL) strategies have been developed over the years
aimed at aiding the students with real-life applications. Although implementation of such
techniques in specialist subjects involving high-end mathematics is somewhat limited, it is
not impossible.
In the beginning of 2012 a decision was made to review the teaching and learning strategies
in Fluid Mechanics unit (ENG480) - the core unit in Mechanical Engineering stream. The
subject deals with physical phenomena occurring when a fluid flows over bodies. Objects of
interest include moving cars, flying airplanes, water-jets, and windmills. It was decided to
offer the students projects involving design-build-test stages, where all testing is conducted in
the wind tunnel.
In 2013 the unit was first run in PBL mode, and although the lecturer received very positive
feedback from the students, lack of appropriate instrumentation was identified as a major
drawback. Not only the students had to address the objectives of the project, but also they had
to design and set up some basic measurement system (Figures 1 and 2). This placed
unnecessary pressure in terms of the additional workload on both the students and the
lecturer. Additionally, given a very tight timeframe, the measurement system was not able to
provide very accurate qualitative results.
Figure 1 Balance to measure the vertical force (Lift).
As the wind blows over the airfoil, it lifts, and the mass
measured by the balance is directly proportional to the
exerted force
Figure 2 'Drag machine' for measurement of the force parallel
to the flow. As the wind blows over the airfoil, the drag
machine moves in the direction of the flow, and the amount
by which the springs have stretched is directly proportional to
the exerted force
Purpose
This aim of this project was therefore the development of a more suitable learning
environment for authentic practice within Engineering through purchasing and installing
additional equipment for the wind tunnel. Not only would this enhance the performance and
expand the range of activities which can be performed using the wind tunnel, but also it
would create new opportunities for research and innovation.
Design and Implementation
Two possible approaches were identified. First, a wind tunnel with all necessary measuring
equipment could be purchased off the shelf (Figure 3). The major drawback of such approach
was found to be the size of models which could be tested and the range of wind speeds which
could be achieved. The wind tunnel shown in Figure 3, for example, would be suitable for a
10x15cm model, and would only allow wind speed of about 150km/hr. A larger wind tunnel
could be found, however the cost would increase dramatically, quite possibly pushing
AU$50,000. Additionally, CDU already has a working wind tunnel which compares well
with equipment available in other Australian universities and overseas. The second option
was therefore to purchase and install additional equipment required to advance it to a suitable
level, and the associated cost was estimated to be AU$5500 at the most.
Figure 3 Armfield low speed bench-top wind tunnel with optional
accessories. Test section is 15cm in diameter (images taken from
Armfield catalogue)
Two undergraduate students selected this project as the focus of their research thesis. The
aspects of the project included the force measurement, flow visualisation and measurement of
pressure and temperature along the surface. Forces to be measured are drag – acting on the
object in the direction of the airflow, and lift – acting in the direction normal to the flow
(upwards). A two-component force balance was constructed which consists of a strut
supported by two load cells orientated perpendicularly, and platform type linkages are used
for decoupling of forces (Figure 4). Three different attachments have been manufactured to
allow for testing of small and large bulk objects, and airfoil type models. Thermocouples are
embedded within the flexible tubes of a 16-channel water-based manometer (Figure 5) which
enables measurement of pressure and temperature distribution along the surface of the object
providing the students with better understanding of fluid patterns. Additionally, a smoke
wand was installed upstream of the test section to enable flow visualization (Figure 6). In
conjunction with the manometer it provides test data of the boundary layer separation,
stalling conditions, and vortex formation. Calibration was conducted on the well-described
models with known characteristics and using digital gauges calibrated by the manufacturer.
Figure 4 Two-component balance for simultaneous measurement of lift and drag (left – schematic, right – actual setup)
Figure 5 Manometer rake for pressure measurement
Figure 6 Demonstration of vortex shedding using
constructed smoke wand
Summary of Outcomes
All installed equipment was used by the students enrolled in ENG480 during March-May
2014. Extensive testing of supersonic wind tunnel inserts, supersonic and subsonic airfoils,
and axial fans was conducted. According to student feedback, the newly installed
instrumentation helped in understanding of complex theoretical concepts which in turn
inspired students to conduct further research in fluid mechanics, including industrial
applications.
The outcomes of this project have been also evaluated against the objectives set in the
University strategic plan, and it was found that at least three points were addressed. A Unique
Learning Environment has been created to improve student experiences and provide grounds for
authentic practice within a highly theoretical engineering subject. In fact, this project has
enabled an opportunity for cutting edge research into aerodynamics at CDU, addressing the
objective of Research with global reach. At this early stage, a research group has already
formed and began working on optimisation of body shapes for less energy consumption
during movement (applications include cars, aircraft, submarines, and the like). This research
involves the study of surface dimpling and has limited representation in the literature
worldwide. Additionally, the facility has been already used to conduct workshops for school
students. New equipment will enable more interactive and interesting demonstrations, which
has potential to lead to higher HE student intake rate, and securing the future for both, School
of Engineering and IT and the students.