Drag Negation has gone public!
Below is the original disclosure taken from my LinkedIn article
Drag Negation Explained.
There are two ways that a solid object may pass through a fluid. The mission for both,
is to move fluid particles aside so that the object may pass. The first way accounts for
all existing designs and works by pushing the fluid particles away from the object. The
second way I call "Drag Negation". It works by forcing fluid particles to take a path
internal to the object. In doing so, it prevents temporarily energised fluid particles from
dissipating their kinetic/pressure/heat energy into ambient fluid. There are a number of
object shapes that allow form drag to be negated. All have in common, an outer surface that
presents no opportunity for form drag. If the object we are moving through a fluid is to
have a payload, we must have volume somewhere and we cannot avoid moving fluid particles
temporarily to make way for the object. Internal to drag negating objects/vehicles, we use
shapes that support energy transforms. Kinetic energy allows the particles to be moved away
from the oncoming payload. The kinetic energy may be transformed into pressure and heat
(compressible fluids) or gravitational potential energy (ships). There may be more. As the
fluid passes the "choke" point, another energy transform is used, that is an inverse of the
original. Within compressible fluids (such as air), pressure and heat enter a rocket nozzle,
and this transforms into kinetic energy just the same way as in any rocket. The image above
shows a "de laval nozzle" shape. This may well be the most efficient drag negating shape of
all. I expect that this shape will be practical for drag negating bullets, missiles etc.
Which kind of touches on the question, what is the scope for this "Drag Negation"? Scope
also includes virtually every type of transport vehicle required to move at speed within air
or within/on water.
Because vehicles to date have simply discarded to ambient, the energy transferred to fluid
particles in order for the vehicle to move, this has resulted in a large amount of heating
in our atmosphere and this is seperate from the heat dissipated by any propulsion system.
Drag Negating vehicles move efficiently through fluids and thus provide far less opportunity
for heating the fluid. In the case of vehicles travelling within Earths atmosphere
(cars, aircraft etc), this also has implications for propulsion systems. We don't need
engines to work as hard, nor to provide enormous thrust to reach and maintain very high
cruising speeds. Reversing climate change would be a very nice thing to do. Time will
eventually tell whether Drag Negation can make a difference. I hope so.
That may be all you need to understand this new paradigm. If not, I include some rather
verbose explanations that cover transforms, and a bit more on Drag Negations history.
A-B-A, pendulums: Consider an air particle and an approaching vehicle. The vehicle is
approaching from the right. Ignoring for now, any left/right movement of the air particle
as the vehicle passes. Focus instead on the fact that it must make a journey from its
original position ("A") to some position through which no part of the vehicle passes. This
may be above or below the vehicle. or even off to one side. Let's call that position "B".
This is not all that is required. We cannot simply leave a vacuum tunnel behind our vehicle.
And so our air particle must make the return journey, from "B" back to "A". The energy for
the entire A-B-A journey must come from somewhere, and in fact it all comes from the kinetic
energy of the moving vehicle. In current systems, during the A-B journey, this air particle
is open to ambience. Because our air particle has more energy than surrounding air
particles, this energy is dissipated into ambient air very quickly. Drag Negation prevents
this dissipation and instead contains it within the vehicle shape. If we use a shape similar
to a de laval nozzle, our payload may be placed in the volume between the internal and
external walls. Looking at our vehicle from the outside, the external walls are in perfect
alignment with the direction of motion. Thus, although surface friction will be present on
the outside surfaces, form drag will not be present in any significant amount. Inside our
vehicle is a different matter. The A-B journey is done within the section from front of
vehicle to the neck. At this point, kinetic and pressure energy within the air particle will
be at its maximum. As the air particle passes the neck, it will start to behave similarly
to hot gases in a rocket nozzle, which I am told is quite efficient in transforming heat
and pressure into thrust. And so the energy for the B-A journey, is derived from that stored
up until the it passes through the neck of our vehicle.
It may be helpful to consider other systems in which using energy transforms are useful in
making efficient, A-B-A journeys. Take the case of water in a fountain. We use a pump to
accelerate water particles, giving them an upward thrust. Energy within these water
particles dissipates to ambient from the moment they leave the pump/pipe arrangement. Let's
assume that to move 100 litres / minute to a height of 1 metre, it requires X amount of
work to be done by our water pump. Now consider the same system, but let's now use a pipe
from our reference point (pond surface for example) to an elevation of 1 metre, and then
returns to the pond surface level. Our A-B-A journey for water particles is complete.
Energy from the pump transforms into pressure at location A, and as the water moves up the
pipe, transforms into gravitational potential. On the return journey, this is reversed.
Although surface friction within the pipe is significantly higher than our original system,
the work required to raise water particles to an elevation of 1 metre, is effectively
neutralised or "negated". Our vehicle which travels through air is similar, in that there
is a penalty applied in negating form drag, in increased surface friction. Because form
drag always increases exponentially with velocity but surface friction does not necessarily
do so, we derive a benefit when the vehicle travels at significant velocity, but at extremely
low velocities, may encounter roughly twice as much total drag, as velocity approaches zero.
Other A-B-A journeys: A pendulum. A childs swing. A pogo stick. A yoyo. A ball bouncing.
In all of these and countless more, whether we realise it or not, we use an energy transform
to make a return journey efficient. Why then, have we not done this with vehicles travelling
through air or water? I suspect this is so because we started with something simple, that
travelled at velocities that were relatively insignificant, and so shapes chosen were
actually efficient for the system under consideration. As the speed of vehicles increased,
we became more focussed with increasing thrust, than increasing aerodynamic efficiency.
Whatever the explanation is, what really matters is that it doesn't need to be the case.
Once the Drag Negation concept is fully understood, we are able to design systems that
travel either through a fluid, or on the boundary between two fluids (eg ship), in a way
that decreases form drag and its exponential relationship with increasing velocity.
The waveguide connection: Our object/vehicle is going to mimic a pulse travelling through a
fluid within a waveguide. Our aim is to travel at significant velocity through a fluid
efficiently. There are things in nature that achieve this already. Pressure waves and gravity
waves. Our DN vehicle itself is designed to be a waveguide, with a propagation mechanism.
It will propagate a pulse, which will be stationary relative to the waveguide, but moving
in relation to the fluid. When the fluid is compressible, a pressure wave is used. For
non-compressible fluids, a gravity wave may be used. The waveguide is what stops the
temporarily energised fluid particles from dissipating energy into surrounding ambient fluid.
History: Around 2003, I was asked to transport a large mattress over considerable distance.
The car I used had a "roof rack". I first placed a very large flat board on the roof rack,
and tied the mattress to this board. In my mind, I decided that I should keep my speed down
to 80 KPH, so that this quite large contraption on my car would not get damaged, or damage
the car. When I encountered my first decent stretch of highway, I accelerated to what I
thought was around 60 KPH, then glancing at the speedometer. It was then that I noticed
that I was already doing over 80 KPH. How was I determining the speed of the car before
looking at the speedometer? By the noise of the air turbulence around the vehicle. When
I looked at the speedometer and saw that the car was already over 80 KPH, I initially
panicked. It didn't make sense. It was too quiet for the speed, and I wasn't giving the
car enough gas to be doing this speed. In a second, I became a bit excited, and instead
of backing off to maintain a speed below 80 KPH, I gave the car a bit more gas. A few seconds
later, at roughly 95 KPH, there was a large "bang" sound, the air turbulence noise returned,
and a large object appeared briefly in my rear vision mirror. The force of the air passing
between the car and the board had resulted in the assembly ripping itself from the vehicle,
damaging the car roof sufficiently that I was unable to reattach the roof rack. I knew that
something significant happened, but I did not at that time understand what the scientific
explanation would be.
Now fast forward to 1st April 2014. I had recently moved house, had purchased some nice sound
equipment and was feeling both happy and relaxed. I was travelling on a highway, when a
prime mover entered the highway from a side road, so I was then travelling behind it. You
know those "fairing" type things that are placed onto prime movers to deflect air over the
trailer? This truck had the largest fairing I'd ever seen, but it wasn't towing a trailer.
I learned later that it had only to go a short distance to where it was about to connect a
trailer. In my youth, I would ride a bicycle to school and being somewhat cheeky, would
ride in the "slipstream" behind the school bus. Or really, any big vehicle that allowed me
to travel fast and efficiently. So on 1st April 2014 I'm in my little car behind this truck
with a massive fairing. I thought about how nice it would be to ride a bicycle behind this
truck, as the slipstream effect would be huge. I got my car close to the truck and confirmed.
As I'd spent countless hours and in fact years writing computer programs, I knew that for
most systems that work in some way, they can be made to work in the inverse way. I then
tried to work out what a vehicle would look like, that produced an "inverse slipstream".
What I came up with (in the space of just a minute or two) was basically the inverse of
a rocket nozzle. A funnel. Over the next few minutes I connected the rest of the dots, in
my mind conceiving a vehicle in which form drag could effectively be negated. When I got
home, I filed provisional patent in Australia just as fast as I could. Just before midnight
this was achieved.
Scope: I like thinking of what Drag Negation can do for the transportation industry.
Personally, I'd like to be able to maintain speeds of 100+ KPH on a human powered vehicle
(level ground). But I suspect we will more likely see electric DN vehicles before human
powered. The point here is that there will be changes to vehicle design due to the
decreased requirement for large engines onboard just to maintain acceptable cruising speeds.
I also like the idea of using compressed air vehicles, particularly indoors or where there
is danger of fire or explosion due to ignition. The same design change outlook will be
present for air vehicles.
If you produce CFD test results you'd like to share, I'm happy to link them in below.
Why give Drag Negation away for free?: Because I tried over a five year period to
commercialise, but failed through a combination of circumstances and lack of trust on the
part of would be helpers, particularly of the investment type. "Climate Change" is a
subject that few will not be concerned about and even fewer that are still unaware of.
Drag Negation is my gift. Enjoy!
http://www.linkedin.com/in/glen-mcdiarmid-7ba00997
Glen McDiarmid
20th April 2019