regex101: Extract between parentheses

Regular Expression

\{([^\{\}]|(?R))*\}

Wind energy is the kinetic energy of air in motion, also called wind. Total wind energy flowing through an imaginary surface with area A during the time t is:
{\displaystyle E={\frac {1}{2}}mv^{2}={\frac {1}{2}}(Avt\rho )v^{2}={\frac {1}{2}}At\rho v^{3},} E={\frac {1}{2}}mv^{2}={\frac {1}{2}}(Avt\rho )v^{2}={\frac {1}{2}}At\rho v^{3},[248]
where ρ is the density of air; v is the wind speed; Avt is the volume of air passing through A (which is considered perpendicular to the direction of the wind); Avtρ is therefore the mass m passing through "A". Note that ½ ρv2 is the kinetic energy of the moving air per unit volume.
Power is energy per unit time, so the wind power incident on A (e.g. equal to the rotor area of a wind turbine) is:
{\displaystyle P={\frac {E}{t}}={\frac {1}{2}}A\rho v^{3}.} P={\frac {E}{t}}={\frac {1}{2}}A\rho v^{3}.[248]
Wind power in an open air stream is thus proportional to the third power of the wind speed; the available power increases eightfold when the wind spe

Extraction

Wind energy is the kinetic energy of air in motion, also called wind. Total wind energy flowing through an imaginary surface with area A during the time t is:
{\displaystyle E={\frac {1}{2}}mv^{2}={\frac {1}{2}}(Avt\rho )v^{2}={\frac {1}{2}}At\rho v^{3},} E={\frac {1}{2}}mv^{2}={\frac {1}{2}}(Avt\rho )v^{2}={\frac {1}{2}}At\rho v^{3},[248]
where ρ is the density of air; v is the wind speed; Avt is the volume of air passing through A (which is considered perpendicular to the direction of the wind); Avtρ is therefore the mass m passing through "A". Note that ½ ρv2 is the kinetic energy of the moving air per unit volume.
Power is energy per unit time, so the wind power incident on A (e.g. equal to the rotor area of a wind turbine) is:
{\displaystyle P={\frac {E}{t}}={\frac {1}{2}}A\rho v^{3}.} P={\frac {E}{t}}={\frac {1}{2}}A\rho v^{3}.[248]
Wind power in an open air stream is thus proportional to the third power of the wind speed; the available power increases eightfold when the wind spe