“…In recent years, the behavior of the flame front during the smoldering combustion on a thin solid (e.g. a sheet of paper) has been vigorously studied both experimentally ( [12,22,28,36,37,38,39]) and mathematically ( [10,13,14,16,17,18,19,20,21]) aspects. The Kuramoto-Sivashinsky (KS) equation ( [23,32]), which is a well-known mathematical model of gaseous combustion, has been applied to research on smoldering combustion ( [12,13,14,20]).…”