I've recently designed a rocket with an unconventional tail end with the idea being to reduce turbulence over the fins therefore making them more effective, however, having built it i'm not so convinced with the science and was hoping there was someone I could bounce my theory off just to let me know if there is any credence to the idea. The rocket flies well, but I don't know if the tail end is related to this or not.
The idea was to have slots cut into the body tube on either side of the fins. Enclosed by the body tube is effectively a conical boat-tail with the theory being to have fast moving air entering this cavity through the slots. As the volume increases towards the rear of this cavity the air should begin to slow down and, using the Bernoulli principle, a decrease in velocity should relate to an increase in pressure. This should mean that an area of high pressure is created at the very rear of the rocket and an area of low pressure at the front of the cavity under the slots leading to a suction effect pulling air over the fins reducing turbulence. However, it has been pointed out to me that on all rockets there is an an area of low pressure at the very rear in the form of base drag. How does this effect the system, and could this system be said to reduce base drag? Furthermore, if this system is working in the first place, does pulling air over the fins reduce turbulence or could it in fact be making the problem worse?
This video shows a 3D drawing of the system, but the slots are not included.
[video=youtube;hikmlKFz7do]https://www.youtube.com/watch?v=hikmlKFz7do[/video]
It could very well be that I am using the Bernoulli principle incorrectly, but any input as to what theoretical effect this system is having to the rockets flight (if any) would be much appreciated.
Thanks
The idea was to have slots cut into the body tube on either side of the fins. Enclosed by the body tube is effectively a conical boat-tail with the theory being to have fast moving air entering this cavity through the slots. As the volume increases towards the rear of this cavity the air should begin to slow down and, using the Bernoulli principle, a decrease in velocity should relate to an increase in pressure. This should mean that an area of high pressure is created at the very rear of the rocket and an area of low pressure at the front of the cavity under the slots leading to a suction effect pulling air over the fins reducing turbulence. However, it has been pointed out to me that on all rockets there is an an area of low pressure at the very rear in the form of base drag. How does this effect the system, and could this system be said to reduce base drag? Furthermore, if this system is working in the first place, does pulling air over the fins reduce turbulence or could it in fact be making the problem worse?
This video shows a 3D drawing of the system, but the slots are not included.
[video=youtube;hikmlKFz7do]https://www.youtube.com/watch?v=hikmlKFz7do[/video]
It could very well be that I am using the Bernoulli principle incorrectly, but any input as to what theoretical effect this system is having to the rockets flight (if any) would be much appreciated.
Thanks