Exemplary embodiments are directed to a cooling apparatus for cooling a power electronic device, the apparatus including at least one panel that is adapted to be thermally connected to a heat source in order to receive heat from the heat source. The panel is also adapted to be thermally in contact with an air flow in order to transfer heat from the panel. The panel includes at least one hole between a first side of the panel and a second side of the panel. The hole is adapted to attenuate a vibrating air pressure generated by an acoustic noise source and carried by the air.