Definition of sound – sound pressure and velocity. Upper, mean, mean square and root mean square values. Frequency, period, wave length, wave number, phase velocity. Plane, cylindrical and spherical waves.
Diffraction of waves – Huygen’s Principle. Reflection of waves. D’Alembert Principle. Harmonic and periodic signals. Fourier series analysis. Frequency spectrum – audible frequency range, octave band, one-third octave band, upper and lower frequency limit, band-width, centre frequency. Frequency filter – low-pass, high-bass, band-pass and band-stop filters. Measures of sound – sound pressure, sound intensity and sound power levels. Addition of sound fields – correlated and uncorrelated sources. Addition of frequency components. Weighted frequency spectrum – A, B, C and D-filters.
Standing and travelling waves. Longitudinal and transversal waves in infinite solids. Wave equation and its solutions in fluids.
After the course, the participant shall be able to:
- Know basic acoustic definitions:
- Define peak value of sound pressure.
- Define mean value of sound pressure.
- Define root mean square value of sound pressure. - Comprehend basic wave types in fluids:
- Explain the characteristics of plane waves.
- Give an example of plane waves from the ‘real world’.
- Explain the characteristics of cylindrical waves.
- Give an example of cylindrical waves from the ‘real world’.
- Explain the characteristics of spherical waves.
- Give an example of spherical waves from the ‘real world’. - Comprehend basic wave types in infinite solids:
- Explain the characteristics of longitudinal waves.
- Give an example of longitudinal waves from the ‘real world’.
- Explain the characteristics of transversal waves.
- Give an example of transversal waves from the ‘real world’. - Comprehend Huygen’s Principle:
- State the principle in his or her own words.
- Identify an example of the principle. - Comprehend D’Alembert Principle:
- State the principle in his or her own words.
- Identify an example of the principle.
- Predicts an outcome based on the principle for harmonic waves. - Apply acoustical methods to new situations:
- Predict the total A-weighted sound power level for the whole audible frequency range from known third-octave band levels
- Calculate the harmonic components of an arbitrary periodic signal
- Computes the resulting sound level of a broad band sound when passed through a frequency filter - Synthesize complex waves from simple waves:
- Combines longitudinal and transversal waves to form bending waves
- Creates standing waves from travelling waves using reflections
- Combines longitudinal and transversal waves to form quasi-longitudinal waves - Comprehend the wave equation:
- Derive the wave equation in fluids
- Determine the solution of wave equation in fluids:
