[quote name='ramana' date='20 June 2013 - 01:25 AM' timestamp='1371671227' post='116685']
So its about 1500 to 2100 feet.
My guess was 500 to 1000 feet. maybe its more draggy.
You think its radar sensing or some other thing?
BTW whats the beta in lbs units?
[/quote]
I didn't get the beta question. By beta are you referring to coefficient of drag or angle of attack? I have discounted the angle of attack in the calculations as the warhead is like a bullet or at worst conical and cross sectional area won't vary too much between the different angles of attack.
Some quick numbers. I haven't used fluid dynamics in a while (ten years). From memory Cd is dimensionless. Cd of a warhead in my opinion is that of a streamlined cone or bullet or even better. This is done to reduce the drag and keep the reynolds number down. Reynolds number(above 10^5) if it increases too much leads to turbulence and flow separation. While engineering the flow the warhead should produce laminar flow as opposed to turbulent flow even at high velocity ranges. cd of 0.1 might be way too much its probably more streamlined. A cone has a cd of 0.5. A bullet has a cd of 0.3. A cd of 0.5 will most likely lead to turbulent flow (Will have to look up reynolds number equations to be sure).
115 to 161 m/s for a cd of 0.5 1 ton to 500kg warhead.
150 to 210 m/s for a cd of 0.3 1ton to 500kg warhead.
The fuze could be triggered by measurements from the accelerometer in the warhead on reaching the right terminal velocity. There are mil grade accelerometers in small packages. I don't know if they have a gyroscope as well for orientation. The non BGRV, MARV, ones are pretty dumb and may not have the gyroscopes. We recently had the system on chip news for the INS. These might enable our warheads to carry an INS if they are sufficiently small. (This is purely speculation though).
Let me see if I can find some of my old fluid dynamics text books to verify these numbers this weekend.
So its about 1500 to 2100 feet.
My guess was 500 to 1000 feet. maybe its more draggy.
You think its radar sensing or some other thing?
BTW whats the beta in lbs units?
[/quote]
I didn't get the beta question. By beta are you referring to coefficient of drag or angle of attack? I have discounted the angle of attack in the calculations as the warhead is like a bullet or at worst conical and cross sectional area won't vary too much between the different angles of attack.
Some quick numbers. I haven't used fluid dynamics in a while (ten years). From memory Cd is dimensionless. Cd of a warhead in my opinion is that of a streamlined cone or bullet or even better. This is done to reduce the drag and keep the reynolds number down. Reynolds number(above 10^5) if it increases too much leads to turbulence and flow separation. While engineering the flow the warhead should produce laminar flow as opposed to turbulent flow even at high velocity ranges. cd of 0.1 might be way too much its probably more streamlined. A cone has a cd of 0.5. A bullet has a cd of 0.3. A cd of 0.5 will most likely lead to turbulent flow (Will have to look up reynolds number equations to be sure).
115 to 161 m/s for a cd of 0.5 1 ton to 500kg warhead.
150 to 210 m/s for a cd of 0.3 1ton to 500kg warhead.
The fuze could be triggered by measurements from the accelerometer in the warhead on reaching the right terminal velocity. There are mil grade accelerometers in small packages. I don't know if they have a gyroscope as well for orientation. The non BGRV, MARV, ones are pretty dumb and may not have the gyroscopes. We recently had the system on chip news for the INS. These might enable our warheads to carry an INS if they are sufficiently small. (This is purely speculation though).
Let me see if I can find some of my old fluid dynamics text books to verify these numbers this weekend.