\(\(a = 1;\)
\)
k00 = 2.40/a;
\(\(ω00 = 2.40/a;\)
\)
k01 = 5.52/a;
\(\(ω01 = 5.52/a;\)
\)
k02 = 8.65/a;
\(\(ω02 = 8.65/a;\)
\)
k20 = 5.14/a;
\(\(ω20 = \ 5.14/a;\)
\)

\(\(\(
\)\(Plot[BesselJ[0, x], {x, 0, 3}]\)\(
\)\)\)

u1[x_, y_, t_, m_, k_, ω_] = 
      If[(x^2) + (y^2) < 1, 
        N[BesselJ[m, k Sqrt[(x^2) + (y^2)]]] *
          Cos[m ArcCos[(y/Sqrt)[0.001 + (x^2) + (y^2)]] ] 
          Cos[t ω], 0]

\(Table[
      Plot3D[u1[x, y, t, 2, k20, ω20], {x, \(-1.1\), 1.1}, {y, 
          \(-1.1\), 1.1}, 
	PlotRange -> {\(-0.8\), 0.8}], {t, 0, 
        2\ Pi/ω20, 0.1}]\)