Natalia Barri

imo.net

Natalia Barri

Institute of Mechanics MSU

Aerodynamical properties of fragments of

a meteor body in the terrestrial

atmosphere

Natalia Barri

n_barri@imec.msu.ru

Lomonosov Moscow State University, Russia


Statement of the problem

■ Two variants of bodies sizes are considered:

α

R R 0.25 and R R 0. 5

2

/

1

=

■ Values of the angle between the center line and an incoming flow

- 0, 15, 30, 45, 60, 75 and 90 º;

■ Values of the distance between the fragments d - 0, 0.2, 0.4, 0.6, 0.8, 1;

d - dimensionless quantity, the distance between the fragments related to

the radius of the biggest sphere;

2

/

1

=

■ All calculations were carried out at value of Mach number

and the adiabatic index γ =1.4

M = 6


Transverse

force coefficient

C r

p


= ∫ p sinθ


2

0.5ρ

∞V∞

S

Σ

ρ V

2 / p = γ M 2



p ∞

V


- pressure in an incoming flow , - density in an incoming flow,

- velocity of an incoming flow, - the area of a sphere’s

θ

midsection, - the polar angle counted from a forward point of sphere.

ρ ∞

S


0.3

C r

d=0.2

d=0.4

0.2

0.1

- 0.1

- 0.2

d=1

C r

0.5

d=0.8

0.4

20 40 60 80

d=0.6

d=0

d=0.8

a

d=0.4

R 1 / R 2 = 0.5

0.3

0.2

d=0.6

d=0.2

d=0

R 1

/ R 2

= 0.25

0.1

- 0.1

20 40 60 80

d=1

a

- 0.2


A display area of the collimation effect

dh_y

y

1.5

1.0

0.5

R 1

/ R 2

= 0.5

R 1

/ R 2

= 0.25

- 1.0 - 0.5 0.5 1.0

d x

h_x

- 0.5

- 1.0

- 1.5


C r

d=1

0.02

d=0.8

d=0.6

20 40 60 80 100 a

- 0.02

d=0.4

- 0.04

- 0.06

d=0.2

- 0.08

- 0.10

d=0

0.01

d=1

d=0.8

d=0.6

- 0.01

- 0.02

C r

R 1 / R 2 = 0.5

20 40 60 80 100 a

d=0.4

R 1

/ R 2

= 0.25

- 0.03

d=0.2

- 0.04

- 0.05

d=0


Drag

coefficient

C d

p


= ∫ p cos θ dσ

ρ

2

0.5

∞V∞

S

Σ

ρ V

2 / p = γ M 2



p ∞

V


ρ ∞

- pressure in an incoming flow , - density in an incoming flow,

- velocity of an incoming flow, - the area of a sphere’s

θ

midsection, - the polar angle counted from a forward point of sphere.

S


C d

R1/ R2= 0.5

1.2

1.0

0.8

D=0

D=0.2

D=0.4

D=0.6

0.6

0.4

0.2

20 40 60 80

a

1.4

1.2

1.0

C d

D=0.6

D=0.2

D=0

D=0.4

0.8

0.6

R 1

/ R 2

= 0.25

0.4

0.2

20 40 60 80

a


R 1 / R 2 = 0.5

R 1

/ R 2

= 0.25

dy

dy

1.5

1.5

1.0

1.0

0.5

0.5

- 1.0 - 0.5 0.5 1.0

dx

- 1.0 - 0.5 0.5 1.0

dx

- 0.5

- 0.5

- 1.0

- 1.0

- 1.5

- 1.5


The basic aerodynamic properties of group

of bodies in a supersonic flow



The collimation effect is shown on a certain range of angles, smaller

fragments are involved in the wake of the leading one. In case of fragments

of the different size the collimation effect shown for smaller bodies b

on a

wider range of angles.

Resistance of the body in the wake is considerably smaller then resistance

of the leading one except for positions where the shock wave of first body

falls on the frontal surface of the backward one.

Primary separation of external fragments from the central part (I.A.(

Zhdan,

V.P. Stulov, , P.V. Stulov (2005) 3D configurations of broken body

fragments in a supersonic flow. Dokl. . Phys. . 50(10), 514–518).

518).


Basic configurations in the process of the

fragment swarm evolution

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