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Archimedes' constant $\pi$

The constant $\pi$ represents the area of the unit circle, the half-period of trigonometric functions, and many other things in mathematics.

Symbol
$\pi$

Default
3.141592653589793

Used in
$A_{ab}$
Cross-sectional area of armour bedding [mm$^2$]
$A_{ar}$
Cross-sectional area of armour [mm$^2$]
$A_c$
Cross-sectional area of conductor [mm$^2$]
$A_{comp}$
Cross-sectional area of compartment [m$^2$]
$A_d$
Cross-sectional area of duct wall [mm$^2$]
$A_{d,fill}$
Free cross-sectional area inside duct [mm$^2$]
$A_{di}$
Surface of duct inner wall [m$^2$]
$A_{do}$
Surface of duct outer wall [m$^2$]
$A_e$
Surface of object [m$^2$]
$A_{encl}$
Cross-sectional area of enclosure [mm$^2$]
$A_{er}$
Surface of object [m$^2$]
$A_f$
Cross-sectional area of filler [mm$^2$]
$A_{hsf}$
Cross-sectional area of fluid [mm$^2$]
$A_{hsi}$
Cross-sectional area of insulation [mm$^2$]
$A_{hsj}$
Cross-sectional area of outer jacket [mm$^2$]
$A_{hsp}$
Cross-sectional area of fluid-filled pipe [mm$^2$]
$A_i$
Cross-sectional area of insulation [mm$^2$]
$A_{it}$
Cross-sectional area of insulation (IEC 60853) [mm$^2$]
$A_j$
Cross-sectional area of jacket [mm$^2$]
$A_{prot}$
Cross-sectional area of protective cover [mm$^2$]
$A_{sc}$
Cross-sectional area of screen [mm$^2$]
$A_{scb}$
Cross-sectional area of screen bedding [mm$^2$]
$A_{scs}$
Cross-sectional area of screen serving [mm$^2$]
$A_{sh}$
Cross-sectional area of sheath [mm$^2$]
$A_{shj}$
Cross-sectional area of sheath jacket [mm$^2$]
$A_{skid}$
Cross-sectional area of skid wires [mm$^2$]
$A_{sp}$
Cross-sectional area of steel pipe [mm$^2$]
$A_t$
Cross-sectional area of the tunnel [m$^2$]
$A_{tape}$
Cross-sectional area of bedding/serving tapes [mm$^2$]
$\beta_1$
Substitution coefficient $\beta_1$ for eddy-currents
$\beta_X$
Crossing angle [rad] [rad]
$C_{ag}$
Capacitance armour - ground [F/m]
$C_b$
Capacitance of insulation [F/m]
$c_c$
Distance between the axis of a conductor and the cable center [mm]
$C_{cs}$
Capacitance conductor - shield [F/m]
$C_E$
Capacitance to earth [F/m]
$C_{g3}$
Factor C3 for partially buried pipes
$C_{sa}$
Capacitance shield - amour [F/m]
$C_{sg}$
Capacitance shield - ground [F/m]
$d_{ct}$
External diameter of conductor for transient calculations [mm]
$D_e$
External diameter of object [mm]
$D_{eq}$
Equivalent diameter of a group of round objects [mm]
$D_f$
External diameter of the filler [mm]
$d_x$
Equivalent diameter of a conductor [mm]
$\delta_{ar}$
Equivalent thickness of armour [mm]
$\Delta \theta_{0x,h}$
Temperature rise of the conductor by source h [K]
$\Delta \theta_{e,t}$
Transient temperature rise of outer surface [K]
$\Delta \theta_{kp}$
Temperature rise by buried object k [K]
$\Delta \theta_{kp,t}$
Transient temperature rise of outer surface by object k [K]
$\Delta \theta_{uh}$
Temperature rise by crossing heat sources at z [K]
$Do_t$
Tunnel/trough outer diameter [m]
$F_{\alpha}$
Inclination derating factor [p.u.]
$F_{eq}$
Factor for envelope circle for a group of equal circles
$F_{ij}$
View factor object-object
$F_{lay,3c}$
Effective length per unit lay length of twisted conductors
$F_{lay,ar}$
Effective length per unit lay length of armour
$F_{lay,c}$
Effective length per unit lay length of conductor strands
$F_{lay,sc}$
Effective length per unit lay length of screen wires
$F_m$
Radiation coefficient mutual
$F_x$
Geometrical distance factor for multi-core cables
$G$
Conductance [S/m]
$G_1$
Geometric factor $G_1$
$G_2$
Geometric factor $G_2$ for cables with separate sheaths
$g_{dry}$
Geometric constant of circle with dried-out soil [p.u.]
$GMR_c$
Geometric mean radius of conductor [m]
$GMR_{sp}$
Geometric mean radius of steel pipe [m]
$H_1$
Component of inductance $H_1$ of armour [H/m]
$H_2$
Component of inductance $H_2$ of armour [H/m]
$h_{ground}$
Heat transfer coefficient buried part of wall to soil [W/(K.m$^2$)]
$h_t$
Inner height [m]
$H_x$
Magnetic field x-component [mH]
$H_y$
Magnetic field y-component [mH]
$I_c$
Conductor current [A]
$I_{EMF}$
Phase current for EMF calculation [A]
$K_A$
Coefficient K to calculate in air
$K_{par}$
Constant $K_{par}$ (Ovuworie)
$K_{vermeer}$
Vermeer constant for convection heat transfer
$L_a$
Self inductance of conductor [H/m]
$L_i$
Inductance of conductor i [H/m]
$L_m$
Inductance (mean) [H/m]
$\lambda_i$
Parameter $\lambda$ for linear density of dielectric losses
$\omega$
Angular frequency [rad/s]
$p_{soil}$
Depth of image source
$\phi_{ar}$
Angle between armour and cable axis [rad]
$Q_{it1}$
Thermal capacitance of insulation, 1st portion (IEC 60853) [J/(m.K)]
$Q_{it2}$
Thermal capacitance of insulation, 2nd portion (IEC 60853) [J/(m.K)]
$q_x$
Factor for characteristic diameter
$r_b$
Equivalent radius of backfill [mm]
$R_{co}$
Standard DC resistance of conductor [$\Omega$/km]
$R_{sw}$
Resistance skywire [$\Omega$/m]
$\rho_{ar}$
Specific electrical resistivity of armour material [$\Omega$.m]
$\rho_c$
Electrical resistivity of conductor material [$\Omega$.m]
$\rho_{sc}$
Specific electrical resistivity of screen material [$\Omega$.m]
$T_1$
Thermal resistance between one conductor and sheath [K.m/W]
$T_2$
Thermal resistance of armour bedding [K.m/W]
$T_3$
Thermal resistance of jacket [K.m/W]
$T_{4d}$
Thermal resistance for daily load cycle [K.m/W]
$T_{4db}$
Correction of thermal resistance for backfill [K.m/W]
$T_{4i}$
Thermal resistance of medium in the duct [K.m/W]
$T_{4ii}$
Thermal resistance of the duct wall [K.m/W]
$T_{4iii}$
Thermal resistance to ambient [K.m/W]
$T_{4pii}$
Thermal resistance of the pipe wall [K.m/W]
$T_{4piii}$
Thermal resistance of the pipe to ambient [K.m/W]
$T_{4ss}$
Steady-state thermal resistance [K.m/W]
$T_{4w}$
Thermal resistance for weekly load cycle [K.m/W]
$T_{4y}$
Thermal resistance for yearly load cycle [K.m/W]
$T_{ab}$
Thermal resistance of armour bedding [K.m/W]
$T_{at}$
Thermal resistance by convection, air to tunnel [K.m/W]
$T_{conv,ce}$
Thermal resistance by convection, conductor to enclosure [K.m/W]
$T_{cs}$
Thermal resistance of conductor shield [K.m/W]
$T_{ct}$
Thermal resistance of conductor tape [K.m/W]
$T_{dsh}$
Thermal resistance of corrugation filling [K.m/W]
$T_e$
External thermal resistance of tunnel [K.m/W]
$T_{hsi}$
Thermal resistance of insulation [K.m/W]
$T_{hsj}$
Thermal resistance of outer jacket [K.m/W]
$T_{hsp}$
Thermal resistance of fluid-filled pipe [K.m/W]
$T_i$
Thermal resistance of insulation [K.m/W]
$T_{ins}$
Thermal resistance of insulation [K.m/W]
$T_{is}$
Thermal resistance of insulation screen [K.m/W]
$T_j$
Thermal resistance of jacket [K.m/W]
$T_{prot}$
Thermal resistance of protective cover [K.m/W]
$T_{riser}$
Thermal resistance of riser/J-tubes in air/water [K.m/W]
$T_{sa}$
Thermal resistance by convection, surface to air [K.m/W]
$T_{scb}$
Thermal resistance of screen bedding [K.m/W]
$T_{scs}$
Thermal resistance of screen serving [K.m/W]
$T_{shj}$
Thermal resistance of sheath jacket [K.m/W]
$T_{st}$
Radiation thermal resistance, surface to tunnel [K.m/W]
$T_{tr}$
Thermal resistance of trough [K.m/W]
$T_{tw}$
Thermal resistance of tunnel wall [K.m/W]
$T_{wall}$
Thermal resistance of pipe wall [K.m/W]
$\tau_{ar}$
Armour angle [rad]
$\theta_{gas}$
Gas temperature [°C]
$U_{partially}$
OHTC of partially buried pipe [W/(K.m$^2$)]
$U_{wall}$
OHTC of pipe wall [W/(K.m$^2$)]
$V_{comp}$
Gas volume [m$^3$]
$W_{conv,ce}$
Convection heat transfer, conductor to enclosure [W/m]
$W_{conv,ext}$
Convection heat transfer, duct to air [W/m]
$W_{conv,gd}$
Convection heat transfer, gas to duct [W/m]
$W_{conv,int}$
Convection heat transfer, object to duct [W/m]
$W_{conv,og}$
Convection heat transfer, object to gas [W/m]
$W_{conv,sa}$
Convection heat transfer, surface to air [W/m]
$W_{de}$
Losses outside of riser/J-tube [W/m]
$W_{rad,ce}$
Radiation heat transfer, conductor to enclosure [W/m]
$W_{rad,ext}$
Radiation heat transfer, duct to air [W/m]
$W_{rad,sa}$
Radiation heat transfer, surface to air [W/m]
$X_1$
Positive sequence reactance [$\Omega$/m]
$X_a$
Self reactance of conductor [$\Omega$/m]
$X_{ap}$
Equivalent mutual reactance between conductors [$\Omega$/m]
$X_{ar}$
Self reactance of armour [$\Omega$/m]
$X_c$
Mutual reactance between middle and outer cables in flat formation with earth return [$\Omega$/m]
$X_{cp}$
Zero-sequence reactance steel pipe [$\Omega$/m]
$X_d$
Reactance steel pipe [$\Omega$/m]
$X_e$
Self reactance of screen/sheath [$\Omega$/m]
$X_{ij}$
Mutual reactance between two conductors i and j [$\Omega$/m]
$X_L$
Mutual reactance between outer cables in flat formation [$\Omega$/m]
$X_m$
Mutual reactance between conductors flat formation without transposition [$\Omega$/m]
$X_{mut}$
Mutual reactance [$\Omega$/m]
$x_p$
Factor for proximity effect of conductors
$x_s$
Factor for skin effect on conductor
$X_s$
Self reactance of screen/sheath [$\Omega$/m]
$X_{S1}$
Reactance section 1 [$\Omega$/m]
$X_{S2}$
Reactance section 2 [$\Omega$/m]
$X_{S3}$
Reactance section 3 [$\Omega$/m]
$X_{sw}$
Reactance skywire [$\Omega$/m]
$Z_{ct}$
Self impedance of earth continuity conductor [$\Omega$/m]
$Z_{kp}$
Impedance between cable k and p in ground [$\Omega$/m]
$Z_{mt}$
Equivalent mutual impedance between earth continuity conductor and any cable [$\Omega$/m]
$\zeta_{er}$
Radiation shape factor for touching cables
$\mathscr{z}_1$
Impedance of conductor outer surface [$\Omega$/m]
$\mathscr{z}_2$
Impedance of insulation between conductor and screen [$\Omega$/m]
$\mathscr{z}_{34}$
Impedance of insulation between shield and armour [$\Omega$/m]
$\mathscr{z}_{3,s}$
Impedance of shield inner surface [$\Omega$/m]
$\mathscr{z}_{3,sc}$
Impedance of screen inner surface [$\Omega$/m]
$\mathscr{z}_{3,sh}$
Impedance of sheath inner surface [$\Omega$/m]
$\mathscr{z}_{4,s}$
Mutual impedance of shield [$\Omega$/m]
$\mathscr{z}_{4,sc}$
Mutual impedance of screen [$\Omega$/m]
$\mathscr{z}_{4,sh}$
Mutual impedance of sheath [$\Omega$/m]
$\mathscr{z}_{56}$
Impedance of jacket [$\Omega$/m]
$\mathscr{z}_{5,s}$
Impedance of shield outer surface [$\Omega$/m]
$\mathscr{z}_{5,sc}$
Impedance of screen outer surface [$\Omega$/m]
$\mathscr{z}_{5,sh}$
Impedance of sheath outer surface [$\Omega$/m]
$\mathscr{z}_6$
Impedance of insulation between screen and sheath [$\Omega$/m]
$\mathscr{z}_g$
Impedance of earth return in ground [$\Omega$/m]
$\mathscr{z}_{gm}$
Impedance of mutual earth return in ground [$\Omega$/m]
$\mathscr{z}_{pin}$
Impedance of armour inner surface [$\Omega$/m]
$\mathscr{z}_{pmut}$
Mutual impedance of armour [$\Omega$/m]
$\mathscr{z}_{pout}$
Impedance of armour outer surface [$\Omega$/m]