, , .
μ ( ) T:
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ρ ( ) B, Δp ΔV / V, :
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, 20 υ ≈ 1480 /, υ ≈ 56 /.
B E (. 1.12):
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E B , 2030 % .
, , - , . , , . , ; , . , , , () , . , , . , .
, , , .
l , x = 0, x = l (. 2.6.5). T.
2.6.5. , . |
:
- y1(x, t) = A cos (ωt + kx) , ;
- y2(x, t) = A cos (ωt kx) , .
x = 0 ( ) y1 y2. .
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. , . , . .
. (x = 0). (x = l), kl = nπ, n . , , , l :
λn fn:
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. . f1 , (f2, f3, ) . . 2.6.5 n = 2.
. , , . ( T) . , () fn. . 2.6.6 , .
2.6.6. , . |
( n) .
, . 20 20 . 20 , 20 . , ( ) ( ). . , .
. ρ p. .
, OX, p(x, t) x t
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. ω, k, λ, υ , (. 2.6):
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. . (. 2.6)
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B , ρ . . , p. 300 /, , ( 0 1 ) 331,5 /, 20 1 343 /. . , . - . , . , (. 3.8), . (1816 .)
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p , ρ , γ , . γ = 1,4. υ = 332 / ( ).
, γ Cp CV (. 3.10). , (. 3.3). :
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T , M , R = 8,314 / . . , . , , (M = 29103 /) υ = 331,5 /, (M = 4103 /) υ = 970 /, (M = 2103 /) υ = 1270 /.
. , , υ = 1480 / ( 20 ), υ = 56 /.
, . , p0 . , : . p0 1010 , 105 . 107 ! p0 104 10 . , , . , 1012! .
, 106 , - .
, , . . , . , , . , , 80 400 , 250 1050 .
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, , . , , (1962340 ), (27,54186 ).
, , f1 (. 2.6). , fn :
fn = nf1, (n = 1, 2, 3...). |
. An (, ); . . . . . 2.7.1 () , . , , .
2.7.1. , . . |
, . , . .
. . 2.7.2 , , (), .
2.7.2. , (1), (2) () (3), (f1 = 220 ). I / I0. |
, . 2.7.2, , .
, , . . , , , . , . p1 p2, ,
p1 = A0 cos ω1t p2 = A0 cos ω2t. |
, p0 = A0.
, , , .
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,
. 2.7.3(1) p1 p2 t. t = 0 , . , t1 . ( ). t2 = 2t1 . . (. 2.7.3 (2)).
( ) T. A
T 2π / Δω. , , T1 T2 , T1 < T2 ( ω1 > ω2). T n (n 1) :
T = nT1 = (n 1)T2. |
:
f Δf , .
510 . .
2.7.3. , . |
, , , . (1842 .).
( ) , . , .
, υ υ , . υ υ . υ .
2.8.1. . . T , . |
. 2.8.1 . , , T. . 2.8.1 :
υT + υT = λ. |
:
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(υ > 0), f > f, (υ < 0), f < f.
2.8.2. . . T , . |
. 2.8.2 , υ. . 2.8.2 :
υt + υT = υ(t T) + λ (υ + υ)T = λ, |
:
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, υ > 0 , , f < f. , υ < 0 f > f.
, , υ υ, :
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f f. υ υ , . -.
(, ) . , υ . -
c . υ > 0, f < f, υ < 0 , f > f.
- ( , ).