Woocommerce set sale price to regular price - 15% discount

woo sale price

function so_31493236_sale_price( $sale_price, $product ) {
    $sale_price = $product->get_regular_price() * 0.15;
    return $sale_price;
}
add_filter( 'woocommerce_get_sale_price', 'so_31493236_sale_price', 10, 2 );