UWE Bristol Engineering showcase 2015

Efficiency of modern day commercial aircraft
has reached a stagnation point.
Improvements in computational fluid
dynamics has allowed for highly effective
aircraft characteristics to be obtained and
proficiency barriers broken with one
exception, the speed. Attempts at breaching
into such high speed areas as supersonic and
hypersonic flow have resulted in wasteful and
inefficient systems. This report investigates
into the possibility of implementing a ‘reverse
design process’ in order to design a vehicle to
capture the pressure along the lower surface
and increase the vehicles overall efficiency,
along with its applicability to commercial
travel. Such vehicles are known as
Waveriders.
A Waverider is a vehicle designed around the
shock of an arbitrary Mach number, therefore
resulting in a higher obtainable lift force and a
higher L/D ratio. This method allows for a
Waverider to be perfectly optimised for a
specific Mach value; however, if such a design
were to deviate from the calculated Mach
limits, it would become less efficient in flight
as a result of induced drag and a resultant loss
of speed would result. This vehicle has the
ability to perform both in high-supersonic and
hypersonic flow conditions, and can also be
termed as a vehicle that has an attached
shock along its entire leading edge in
comparison to other hypersonic designs
where the shock is separate. Such a design is
generated from a know flowfield created by
an axisymmetric shape such as the cone
below:
Liam Parker
M.Eng Aerospace Engineering
The Design and Evaluation of a High-Speed Supersonic
Waverider using CFD Streamline Tracing Techniques
A streamline tracing technique was used
using CFD as the below image signifies.
Such a streamline tracing technique is used for the
lower surface, allowing the following Waverider
geometries to be generated.
The shock along the compression surface
is shown below:
Four designs were analysed and the
resultant values can be seen below:
Waverider Lift
Design (N)
1 957
392
2 967
219
3 988
677
4 100
108
0
Drag (N) L/D Total Total
(2dp) Elements Nodes
263602.4 3.632 34642987 5800565
275013.7 3.517 34536845 5799234
282382.9 3.5012 34568372 5810234
293539.5 3.410 34918753 5810356
The optimal design has been rendered
below:
Project Supervisor
Dr Chris Toomer
Project Summary
Efficiency of modern day commercial aircraft has reached a
stagnation point. Improvements in computational fluid dynamics
has allowed for highly effective aircraft characteristics to be
obtained and proficiency barriers broken with one exception, the
speed. Attempts at breaching into such high speed areas as
supersonic and hypersonic flow have resulted in wasteful and
inefficient systems. This report investigates into the possibility of
implementing a ‘reverse design process’ in order to design a
vehicle to capture the pressure along the lower surface and
increase the vehicles overall efficiency, along with its applicability
to commercial travel. Such vehicles are known as Waveriders. Six
Waverider designs were constructed within this report.
Project Objectives
The first objective of this report is to create a Waverider design
through analytical and mathematical means, in order to determine
whether the idea of shaping a vehicle around a shock does indeed
improve its efficiency. The second objective is to see if further
improvements in the aircrafts efficiency can occur through other
means and techniques employed on high-speed aircraft, along with
a view to determine whether Waverider technology is a feasible
option for future commercial travel.
Project Conclusion
It was concluded that a lower wetted surface does not guarantee a
more efficient vehicle (resulting from less drag). A vehicle with a
lower surface area returned with a lower aerodynamic efficiency of
3.298, a difference of 0.334 in comparison to Design one.
However, this may be in relation to the reduced length of the
vehicle which transpired due to the loft cut technique used for
Waverider generation.
Design one appeared to follow the trends of Kutchemann’s
formula, confirming the deterioration of efficiency with Mach
number. However, Ferguson’s Waverider appeared to increase
with Mach number. The initial Mach number the Waverider was
designed around may have been higher than the maximum value
observed from Figure 51, therefore its efficiency may dip after such
a point in order to match the trend calculated by Kuchemann.
Therefore to conclude, obtaining an ideal solution for such a design
is unfeasible upon following a non-iterative process. Nevertheless,
Waveriders do produce higher levels of flight efficiency in
comparison to standard supersonic and hypersonic configurations,
therefore they do appear to be the optimal approach in achieving
efficient, high-speed vehicle configurations for future high-speed
travel in the future.