Getting the overall color to look like a warm sunset is as easy as setting the white balance a little warm. But one of the things that makes golden hour so special is the direction of that warm light. To simulate that you need to use a strong source of light shining on your model or subject from a relatively low angle. And you need to be able to shoot without revealing conflicting shadows cast by the real sun, so it works best on a cloudy day.

Even in the middle of a cloudy, gray day you can make it look like golden hour, But you're going to need to use some off camera flash to get it just right. This video demonstrates this perfectly. The photographer used a portable studio style flash (Elinchrom Quadra A-Head) with a beauty dish and a diffused cover as his main light. He set white balance to 5600K. For the directional light simulating the sun he put a full CTO gel on an SB900 and moved it around throughout the shoot. He even left it in the edge of the field of view for some shots and the photos looked like it was the sun low near the horizon.

Part of the magic of blue hour can be the glow of artificial lighting, even distant ones, coming from streets, signs on shops, neon lights in the windows of restaurants and so on. This is much harder to simulate. Apart from that, adjusting white balance will again go a long way as long as the sun is not casting any shadows, so you can only simulate blue hour for any kind of wide open shot when the sky is completely overcast. If the sky is clear and the sun is high in the sky, you're going to either need a LOT of flash power to overcome the harsh shadows or you're going to have to shoot with your entire field of view in the shadows.