  The aim of this work was to use a multi-approach technique to derive the most
accurate values possible of the physical parameters of the \delta Sct star
HD174966. In addition, we searched for a periodic pattern in the frequency
spectra with the goal of using it to determine the mean density of the star.
First, we extracted the frequency content from the CoRoT light curve. Then, we
derived the physical parameters of HD174966 and carried a mode identification
out from the spectroscopic and photometric observations. We used this
information to look for the models fulfilling all the conditions and discussed
the inaccuracies of the method because of the rotation effects. In a final
step, we searched for patterns in the frequency set using a Fourier transform,
discussed its origin and studied the possibility of using the periodicity to
obtain information about the physical parameters of the star. A total of 185
peaks were obtained from the Fourier analysis of the CoRoT light curve, being
almost all reliable pulsating frequencies. From the spectroscopic observations,
18 oscillation modes were detected and identified, and the inclination angle
($62.5^{\circ}$$^{+7.5}_{-17.5}$) and the rotational velocity of the star (142
km/s) were estimated. From the multi-colour photometric observations, 3
frequencies were detected, which correspond to the main ones in the CoRoT light
curve. We looked for periodicities within the 185 frequencies and found a
periodic pattern ~64 \mu Hz. Using the inclination angle, the rotational
velocity and an Echelle diagram, showing a double comb outside the asymptotic
regime, we concluded that the periodicity corresponds to a large separation
structure. The periodic pattern allowed us to discriminate models from a grid,
finding that the value of the mean density is achieved with a 6% uncertainty.
So, the pattern could be used as a new observable for A-F type stars.
