Formula Symbols - D

Written by Jerry Ratzlaff on . Posted in Nomenclature & Symbols for Engineering, Mathematics, and Science

For other symbols see:  A - B - C - D - E - F - G - H - I - J - K - L - M - N - O - P - Q - R - S - T - U - V - W - X - Y - Z

SymbolGreek SymbolDefinitionUSMetric
\(\delta \;or\; \lambda\) delta , lambda dampening coefficient - -
\(C_f \;or\; f_D\) - Darcy friction factor dimensionless number dimensionless number
\(Da\) - Darcy's law - -
\(Da\) - Darcy number dimensionless number dimensionless number
\(DW\) - Darcy-Weisbach equation dimensionless number dimensionless number
\(De\) - Deborah number dimensionless number dimensionless number
\(w_d\) - Debye angular frequency - -
\(q_d\) - Debye angular wave number - -
\(\lambda_d\) lambda Debye length - -
\(\Theta_d\) Theta Debye temperature - -
\(D\) - Debye-Waller factor - -
\(\lambda\) lambda decay constant - -
\(d\) - deceleration \(ft\;/\;sec^2\) \(m\;/\;s^2\)
\(d\) - deflection - -
\(\delta\) delta deformation \(in \;or\; ft\) \(mm \;or\; m\)
\(x\) - degree of ionization - -
\(\mu\) mu degree of saturation - -
\(F\) - degrees of freedom - -
\(\rho\) rho density \(lb\;/\;ft^3\) \(kg\;/\;m^3\)
\(\rho_f\) rho density (fluid) \(lb\;/\;ft^3\) \(kg\;/\;m^3\)
\(N_e \;or\; \rho\) rho density of state - -
\(z\) - depth \(in \;or\; ft\) \(mm \;or\; m\)
\(\partial\) partial derivative (rate of change) - -
\(d\) - diameter \(in \;or\; ft\) \(mm \;or\; m\)
\(P\) - dielectric polarization - -
\(d \;or\; \Delta\) delta differential - -
\(D \;or\; D_n \;,\; D_p\) - diffusion coefficient \(lbf\) \(N\)
\(L_n \;or\; L_p\) - diffusion length - -
\(\alpha\) alpha diffusivity \(ft^2\;/\;hr\) \(m^2\;/\;s\)
\(a \;or\; b\) - dimension \(in \;or\; ft\) \(mm \;or\; m\)
\(k_d\) - dimensional constant - -
\(n\) - dimensionless exponent - -
\(K\) - dimensionless factor - -
\(N\) - dimensionless number - -
\(\mu \;or\; C_d\) mu discharge coefficient - -
\(d \;or\; \vec{d} \;or\; s\) - displacement \(in \;or\; ft\) \(mm \;or\; m\)
\( \vec{D}\) - displacement current - -
\(\psi \;or\; \delta\) psi , delta dissipation factor - -
\(E_d\) - dissociation energy - -
\(d \;or\; l \;or\; x \;or\; y\) - distance \(in \;or\; ft\) \(mm \;or\; m\)
\(s\) - distance along cable \(in \;or\; ft\) \(mm \;or\; m\)
\(a\) - distance to lowest cable point \(in \;or\; ft\) \(mm \;or\; m\)
\(w\) - distributed load \(lbf \;/\; ft\) \(N \;/\; m\)
\(E_d\) - donor ionization energy - -
\(D\) - draft \(in-wg\) kPa
\(C_d\) - drag coefficient dimensionless number dimensionless number
\(F_d\) - drag force \(lbf\) \(N\)
\(v_{dr}\) - drift velocity - -
\(\zeta\) zeta dryness fraction - -
\(T_d\) - dewpoint temperature \(F\) \(C\)
\(Du\) - Dukhin number dimensionless number dimensionless number
\(Q \;or\; q\) - dynamic pressure - -
\(a\) - dynamic speed constant \(ft \;/\; min\) -
\(\mu \;or\; \eta\) mu (used in mechanical), eta (used in chemical) dynamic viscosity \(ft-lbf\;/\;ft^2-sec\) \(mPa-s\)