Influence of Wind Turbulence on Aerodynamic Admittances of a Streamlined Bridge Deck at Different Angles of Attack

Acknowledgments

Notation

B = 2b

bridge deck width;

$C_i^{\mathrm{\prime }}(i=D,L,M)$

static force coefficients and their derivatives with respect to angle of attack;

coh_j(η, f) (j = D, L, M, u, w)

coherence functions of buffeting forces and turbulence;

D

drag;

|F_j(k, f) |²

correction functions, which represent the normalized two-wavenumber admittances;

f

frequency;

f_ps, f_hs, f_αs

frequencies of lateral, vertical, and torsional modes;

$\tilde{f}=2\pi fb/U$

nondimensional frequency;

I_s

moment of inertia per unit length of the bridge;

I_u

turbulence intensity of u-component of turbulence;

I_w

turbulence intensity of w-component of turbulence;

|J_j(f)|²(j = D, L, M)

joint acceptance functions;

k

wavenumber;

$\tilde{k}=2\pi kb$

nondimensional wavenumber;

L

lift, (L is also used for span length in very limited cases);

$L_j^x(j=u,w)$

longitudinal integral length scales of turbulence;

$L_j^y(j=u,w)$

spanwise integral length scales of turbulence;

M

moment;

m_s

mass per unit length of the bridge;

Q

integrated buffeting force or generalized buffeting force;

R(f)

ratio of generalized force spectra with respect to that based on the strip theory;

S_j(f)(j = D, L, M, u, w)

power spectra of buffeting forces and turbulence;

S_j(η, f)(j = D, L, M, u, w)

cross-power spectra of buffeting forces and turbulence;

S_j(k, f) (j = D, L, M, u, w)

wavenumber–frequency (two-wavenumber) spectra of buffeting forces and turbulence;

t

time;

U

mean wind velocity;

u

longitudinal component of turbulence;

w

vertical component of turbulence;

χ_ij(f) (i = D, L, M;j = u, w)

one-wavenumber aerodynamic admittances;

${\chi }_j^{2D}(f)(i=D,L,M)$

2D aerodynamic admittances;

χ_ij(k, f) (i = D, L, M;j = u, w)

two-wavenumber aerodynamic admittances;

δ = L/B

aspect ratio between span length and section width;

Δy

spanwise separation;

η

separation distance between two spanwise locations;

Φ_j(k, f)(j = D, L, M, u, w)

wavenumber–frequency coherence functions;

${\lambda }_1^y,{\lambda }_2^y$

constants of the model of spanwise cross-correlation coefficient;

ρ

air density; and

${\rho }_j\left(\frac{\mathrm{\Delta }y}{B}\right)(j=D,L,M,u,w)$

spanwise cross-correlation coefficient functions of buffeting forces and turbulence.

References