  We present a user-friendly open-source
MATLAB\textsuperscript{\textregistered} package developed by the research group
Turbulence, Wind energy and Stochastics (TWiSt) at the Carl von Ossietzky
University of Oldenburg. Firstly, this package helps the user to perform a very
basic statistical analysis of a given turbulent data set which we believe to be
useful to the entire turbulence community. It can be used to estimate the
statistical quantities of turbulence such as the spectrum density, turbulent
intensity, integral length scale, Taylor microscale, Kolmogorov scale and
dissipation rate. Different well-known methods available in the literature were
selected so that they can be compared. Secondly, this package also performs an
advanced analysis which includes the scale-dependent statistical description of
turbulent cascade using the Fokker-Planck equation which consequently leads to
the assessment of integral fluctuation theorem. This is utilized to estimate
velocity increments, structure functions and their scaling exponents, drift and
diffusion coefficients of the Fokker-Planck equation and consequently the total
entropy production of the turbulent cascade. As a precondition for the
stochastic process approach, Markovian properties of the turbulent cascade in
scale are tested. The knowledge of a Fokker-Planck equation allows to determine
for each independent cascade trajectories a total entropy production. The
estimation of total entropy production allows to verify a rigorous law of
non-equilibrium stochastic thermodynamics, namely the integral fluctuation
theorem, which must be valid if Markov properties hold and the Fokker-Planck
equation is correct. This approach to the turbulent cascade process has the
potential for a new way to link the statistical description of turbulence,
non-equilibrium stochastic thermodynamics and local turbulent flow structures.
