def METHOD_NAME(self):
    if self.get_config('drift:vertical_mixing') is True:
        if self.get_config('vertical_mixing:mixingmodel') == 'randomwalk':
            logger.debug('Turbulent mixing of particles using random walk')
            self.vertical_mixing()
        if self.get_config('vertical_mixing:mixingmodel') == 'analytical':
            logger.debug('Submerging according to wind')
            self.elements.z = -np.random.exponential(
                scale=self.environment.ocean_vertical_diffusivity/
                        self.elements.terminal_velocity,
                size=self.num_elements_active())