Abstract:
Grass has a high leaf density
and requires minimum space to grow. This
experiment was designed to determine the
sound absorption behaviour of six grass
species (Zoysia matrella (L) Merr.,
Stenotaphrum dimidiatum(L.) Brongn,
Panicum repens (L.), Eleusine indica (L.)
Gaertn., Axonopus compressus (Sw) P.
Beauv, and Ischaemum sp.) for their possible
use as noise screens. The sound absorption
of each morphological leaf structure was
studied. For Sound Absorption Coefficients
(SAC) (α) studies, the reverberation room
method under ISO 345:2003 standards was
followed. A B&K dodecahedron Omnidirectional
speaker, power amplifier, and
2250L handheld analyser were used for
reverberation time and RT60 measurements.
Microscopic images of grass leaves were
analysed using ImageJ software. This study
revealed that grasses with the highest and
lowest SAC for higher noise frequencies (>
1500 Hz) are S. dimidiatum Brongn and A.
compressus, respectively. The SAC of S.
dimidiatum Brongn positively correlated
with noise frequency. In general, the
correlation of SAC (α) with noise frequency
(f) is in the form of log10α = a1log10f + b1
where a1 and b1 are grass type-dependent
constants. The morphological parameters
like total leaf area, total sample area, plant
height, and sample dry weight strongly
correlated with the SAC. But leaf thickness,
length, width, surface area, and the weight of
the sample poorly correlated with SAC in the
frequency range.
